diff --git a/Troubleshooting.md b/Troubleshooting.md
index 525df0154e..e6f21034fe 100644
--- a/Troubleshooting.md
+++ b/Troubleshooting.md
@@ -313,6 +313,8 @@ Note: For newer Gson versions these rules might be applied automatically; make s
 
 **Symptom:** A `JsonIOException` with the message 'Abstract classes can't be instantiated!' is thrown; the class mentioned in the exception message is not actually `abstract` in your source code, and you are using the code shrinking tool R8 (Android app builds normally have this configured by default).
 
+Note: If the class which you are trying to deserialize is actually abstract, then this exception is probably unrelated to R8 and you will have to implement a custom [`InstanceCreator`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/InstanceCreator.html) or [`TypeAdapter`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) which creates an instance of a non-abstract subclass of the class.
+
 **Reason:** The code shrinking tool R8 performs optimizations where it removes the no-args constructor from a class and makes the class `abstract`. Due to this Gson cannot create an instance of the class.
 
 **Solution:** Make sure the class has a no-args constructor, then adjust your R8 configuration file to keep the constructor of the class. For example:
@@ -324,6 +326,10 @@ Note: For newer Gson versions these rules might be applied automatically; make s
 }
 ```
 
+You can also use `<init>(...);` to keep all constructors of that class, but then you might actually rely on `sun.misc.Unsafe` on both JDK and Android to create classes without no-args constructor, see [`GsonBuilder.disableJdkUnsafe()`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/GsonBuilder.html#disableJdkUnsafe()) for more information.
+
 For Android you can add this rule to the `proguard-rules.pro` file, see also the [Android documentation](https://developer.android.com/build/shrink-code#keep-code). In case the class name in the exception message is obfuscated, see the Android documentation about [retracing](https://developer.android.com/build/shrink-code#retracing).
 
-Note: If the class which you are trying to deserialize is actually abstract, then this exception is probably unrelated to R8 and you will have to implement a custom [`InstanceCreator`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/InstanceCreator.html) or [`TypeAdapter`](https://javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/TypeAdapter.html) which creates an instance of a non-abstract subclass of the class.
+For Android you can alternatively use the [`@Keep` annotation](https://developer.android.com/studio/write/annotations#keep) on the class or constructor you want to keep. That might be easier than having to maintain a custom R8 configuration.
+
+Note that the latest Gson versions (> 2.10.1) specify a default R8 configuration. If your class is a top-level class or is `static`, has a no-args constructor and its fields are annotated with Gson's [`@SerializedName`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/SerializedName.html), you might not have to perform any additional R8 configuration.
diff --git a/examples/android-proguard-example/README.md b/examples/android-proguard-example/README.md
index 942477d71a..902960fdfa 100644
--- a/examples/android-proguard-example/README.md
+++ b/examples/android-proguard-example/README.md
@@ -12,6 +12,9 @@ details on how ProGuard can be configured.
 The R8 code shrinker uses the same rule format as ProGuard, but there are differences between these two
 tools. Have a look at R8's Compatibility FAQ, and especially at the [Gson section](https://r8.googlesource.com/r8/+/refs/heads/main/compatibility-faq.md#gson).
 
-Note that newer Gson versions apply some of the rules shown in `proguard.cfg` automatically by default,
+Note that the latest Gson versions (> 2.10.1) apply some of the rules shown in `proguard.cfg` automatically by default,
 see the file [`gson/META-INF/proguard/gson.pro`](/gson/src/main/resources/META-INF/proguard/gson.pro) for
-the Gson version you are using.
+the Gson version you are using. In general if your classes are top-level classes or are `static`, have a no-args constructor and their fields are annotated with Gson's [`@SerializedName`](https://www.javadoc.io/doc/com.google.code.gson/gson/latest/com.google.gson/com/google/gson/annotations/SerializedName.html), you might not have to perform any additional ProGuard or R8 configuration.
+
+An alternative to writing custom keep rules for your classes in the ProGuard configuration can be to use
+Android's [`@Keep` annotation](https://developer.android.com/studio/write/annotations#keep).
diff --git a/gson/pom.xml b/gson/pom.xml
index 0e120d3e44..9a48ef4ded 100644
--- a/gson/pom.xml
+++ b/gson/pom.xml
@@ -62,7 +62,7 @@
     <dependency>
       <groupId>com.google.guava</groupId>
       <artifactId>guava-testlib</artifactId>
-      <version>32.0.1-jre</version>
+      <version>32.1.1-jre</version>
       <scope>test</scope>
     </dependency>
   </dependencies>
diff --git a/gson/src/main/java/com/google/gson/GsonBuilder.java b/gson/src/main/java/com/google/gson/GsonBuilder.java
index 217beebb6e..68eb7d718b 100644
--- a/gson/src/main/java/com/google/gson/GsonBuilder.java
+++ b/gson/src/main/java/com/google/gson/GsonBuilder.java
@@ -58,8 +58,7 @@
  * use {@code new Gson()}. {@code GsonBuilder} is best used by creating it, and then invoking its
  * various configuration methods, and finally calling create.</p>
  *
- * <p>The following is an example shows how to use the {@code GsonBuilder} to construct a Gson
- * instance:
+ * <p>The following example shows how to use the {@code GsonBuilder} to construct a Gson instance:
  *
  * <pre>
  * Gson gson = new GsonBuilder()
@@ -125,7 +124,7 @@ public GsonBuilder() {
    * Constructs a GsonBuilder instance from a Gson instance. The newly constructed GsonBuilder
    * has the same configuration as the previously built Gson instance.
    *
-   * @param gson the gson instance whose configuration should by applied to a new GsonBuilder.
+   * @param gson the gson instance whose configuration should be applied to a new GsonBuilder.
    */
   GsonBuilder(Gson gson) {
     this.excluder = gson.excluder;
@@ -279,7 +278,7 @@ public GsonBuilder serializeNulls() {
    * {"x":2,"y":3}}.
    *
    * <p>Given the assumption above, a {@code Map<Point, String>} will be
-   * serialize as an array of arrays (can be viewed as an entry set of pairs).
+   * serialized as an array of arrays (can be viewed as an entry set of pairs).
    *
    * <p>Below is an example of serializing complex types as JSON arrays:
    * <pre> {@code
@@ -601,7 +600,7 @@ public GsonBuilder setDateFormat(String pattern) {
   }
 
   /**
-   * Configures Gson to to serialize {@code Date} objects according to the style value provided.
+   * Configures Gson to serialize {@code Date} objects according to the style value provided.
    * You can call this method or {@link #setDateFormat(String)} multiple times, but only the last
    * invocation will be used to decide the serialization format.
    *
@@ -622,7 +621,7 @@ public GsonBuilder setDateFormat(int style) {
   }
 
   /**
-   * Configures Gson to to serialize {@code Date} objects according to the style value provided.
+   * Configures Gson to serialize {@code Date} objects according to the style value provided.
    * You can call this method or {@link #setDateFormat(String)} multiple times, but only the last
    * invocation will be used to decide the serialization format.
    *
diff --git a/gson/src/main/java/com/google/gson/internal/ConstructorConstructor.java b/gson/src/main/java/com/google/gson/internal/ConstructorConstructor.java
index 7d2dc9b622..0f488a9bb9 100644
--- a/gson/src/main/java/com/google/gson/internal/ConstructorConstructor.java
+++ b/gson/src/main/java/com/google/gson/internal/ConstructorConstructor.java
@@ -76,14 +76,15 @@ static String checkInstantiable(Class<?> c) {
     if (Modifier.isAbstract(modifiers)) {
       // R8 performs aggressive optimizations where it removes the default constructor of a class
       // and makes the class `abstract`; check for that here explicitly
-      if (c.getDeclaredConstructors().length == 0) {
-        return "Abstract classes can't be instantiated! Adjust the R8 configuration or register"
-            + " an InstanceCreator or a TypeAdapter for this type. Class name: " + c.getName()
-            + "\nSee " + TroubleshootingGuide.createUrl("r8-abstract-class");
-      }
-
-      return "Abstract classes can't be instantiated! Register an InstanceCreator"
-          + " or a TypeAdapter for this type. Class name: " + c.getName();
+      /*
+       * Note: Ideally should only show this R8-specific message when it is clear that R8 was
+       * used (e.g. when `c.getDeclaredConstructors().length == 0`), but on Android where this
+       * issue with R8 occurs most, R8 seems to keep some constructors for some reason while
+       * still making the class abstract
+       */
+      return "Abstract classes can't be instantiated! Adjust the R8 configuration or register"
+          + " an InstanceCreator or a TypeAdapter for this type. Class name: " + c.getName()
+          + "\nSee " + TroubleshootingGuide.createUrl("r8-abstract-class");
     }
     return null;
   }
diff --git a/gson/src/main/java/com/google/gson/reflect/TypeToken.java b/gson/src/main/java/com/google/gson/reflect/TypeToken.java
index 4a695666c8..3921a70b64 100644
--- a/gson/src/main/java/com/google/gson/reflect/TypeToken.java
+++ b/gson/src/main/java/com/google/gson/reflect/TypeToken.java
@@ -337,9 +337,12 @@ public static <T> TypeToken<T> get(Class<T> type) {
    * As seen here the result is a {@code TypeToken<?>}; this method cannot provide any type safety,
    * and care must be taken to pass in the correct number of type arguments.
    *
+   * <p>If {@code rawType} is a non-generic class and no type arguments are provided, this method
+   * simply delegates to {@link #get(Class)} and creates a {@code TypeToken(Class)}.
+   *
    * @throws IllegalArgumentException
-   *   If {@code rawType} is not of type {@code Class}, if it is not a generic type, or if the
-   *   type arguments are invalid for the raw type
+   *   If {@code rawType} is not of type {@code Class}, or if the type arguments are invalid for
+   *   the raw type
    */
   public static TypeToken<?> getParameterized(Type rawType, Type... typeArguments) {
     Objects.requireNonNull(rawType);
@@ -354,10 +357,16 @@ public static TypeToken<?> getParameterized(Type rawType, Type... typeArguments)
     Class<?> rawClass = (Class<?>) rawType;
     TypeVariable<?>[] typeVariables = rawClass.getTypeParameters();
 
-    // Note: Does not check if owner type of rawType is generic because this factory method
-    // does not support specifying owner type
-    if (typeVariables.length == 0) {
-      throw new IllegalArgumentException(rawClass.getName() + " is not a generic type");
+    int expectedArgsCount = typeVariables.length;
+    int actualArgsCount = typeArguments.length;
+    if (actualArgsCount != expectedArgsCount) {
+      throw new IllegalArgumentException(rawClass.getName() + " requires " + expectedArgsCount +
+          " type arguments, but got " + actualArgsCount);
+    }
+
+    // For legacy reasons create a TypeToken(Class) if the type is not generic
+    if (typeArguments.length == 0) {
+      return get(rawClass);
     }
 
     // Check for this here to avoid misleading exception thrown by ParameterizedTypeImpl
@@ -366,13 +375,6 @@ public static TypeToken<?> getParameterized(Type rawType, Type... typeArguments)
           + " it requires specifying an owner type");
     }
 
-    int expectedArgsCount = typeVariables.length;
-    int actualArgsCount = typeArguments.length;
-    if (actualArgsCount != expectedArgsCount) {
-      throw new IllegalArgumentException(rawClass.getName() + " requires " + expectedArgsCount +
-          " type arguments, but got " + actualArgsCount);
-    }
-
     for (int i = 0; i < expectedArgsCount; i++) {
       Type typeArgument = Objects.requireNonNull(typeArguments[i], "Type argument must not be null");
       Class<?> rawTypeArgument = $Gson$Types.getRawType(typeArgument);
diff --git a/gson/src/main/resources/META-INF/proguard/gson.pro b/gson/src/main/resources/META-INF/proguard/gson.pro
index c9f235e95b..59d3bb441d 100644
--- a/gson/src/main/resources/META-INF/proguard/gson.pro
+++ b/gson/src/main/resources/META-INF/proguard/gson.pro
@@ -13,7 +13,7 @@
 
 # Keep Gson annotations
 # Note: Cannot perform finer selection here to only cover Gson annotations, see also https://stackoverflow.com/q/47515093
--keepattributes *Annotation*
+-keepattributes RuntimeVisibleAnnotations,AnnotationDefault
 
 
 ### The following rules are needed for R8 in "full mode" which only adheres to `-keepattribtues` if
@@ -24,10 +24,10 @@
 -keep class com.google.gson.reflect.TypeToken { *; }
 
 # Keep any (anonymous) classes extending TypeToken
--keep class * extends com.google.gson.reflect.TypeToken
+-keep,allowobfuscation class * extends com.google.gson.reflect.TypeToken
 
 # Keep classes with @JsonAdapter annotation
--keep @com.google.gson.annotations.JsonAdapter class *
+-keep,allowobfuscation,allowoptimization @com.google.gson.annotations.JsonAdapter class *
 
 # Keep fields with @SerializedName annotation, but allow obfuscation of their names
 -keepclassmembers,allowobfuscation class * {
@@ -35,7 +35,9 @@
 }
 
 # Keep fields with any other Gson annotation
--keepclassmembers class * {
+# Also allow obfuscation, assuming that users will additionally use @SerializedName or
+# other means to preserve the field names
+-keepclassmembers,allowobfuscation class * {
   @com.google.gson.annotations.Expose <fields>;
   @com.google.gson.annotations.JsonAdapter <fields>;
   @com.google.gson.annotations.Since <fields>;
@@ -44,15 +46,25 @@
 
 # Keep no-args constructor of classes which can be used with @JsonAdapter
 # By default their no-args constructor is invoked to create an adapter instance
--keep class * extends com.google.gson.TypeAdapter {
+-keepclassmembers class * extends com.google.gson.TypeAdapter {
   <init>();
 }
--keep class * implements com.google.gson.TypeAdapterFactory {
+-keepclassmembers class * implements com.google.gson.TypeAdapterFactory {
   <init>();
 }
--keep class * implements com.google.gson.JsonSerializer {
+-keepclassmembers class * implements com.google.gson.JsonSerializer {
   <init>();
 }
--keep class * implements com.google.gson.JsonDeserializer {
+-keepclassmembers class * implements com.google.gson.JsonDeserializer {
   <init>();
 }
+
+# If a class is used in some way by the application, and has fields annotated with @SerializedName
+# and a no-args constructor, keep those fields and the constructor
+# Based on https://issuetracker.google.com/issues/150189783#comment11
+# See also https://github.com/google/gson/pull/2420#discussion_r1241813541 for a more detailed explanation
+-if class *
+-keepclasseswithmembers,allowobfuscation,allowoptimization class <1> {
+  <init>();
+  @com.google.gson.annotations.SerializedName <fields>;
+}
diff --git a/gson/src/test/java/com/google/gson/GsonTest.java b/gson/src/test/java/com/google/gson/GsonTest.java
index 9929c0495b..a8e8e88b98 100644
--- a/gson/src/test/java/com/google/gson/GsonTest.java
+++ b/gson/src/test/java/com/google/gson/GsonTest.java
@@ -17,7 +17,7 @@
 package com.google.gson;
 
 import static com.google.common.truth.Truth.assertThat;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.assertThrows;
 
 import com.google.gson.Gson.FutureTypeAdapter;
 import com.google.gson.internal.Excluder;
@@ -109,12 +109,8 @@ private static final class TestTypeAdapter extends TypeAdapter<Object> {
   @Test
   public void testGetAdapter_Null() {
     Gson gson = new Gson();
-    try {
-      gson.getAdapter((TypeToken<?>) null);
-      fail();
-    } catch (NullPointerException e) {
-      assertThat(e).hasMessageThat().isEqualTo("type must not be null");
-    }
+    NullPointerException e = assertThrows(NullPointerException.class, () -> gson.getAdapter((TypeToken<?>) null));
+    assertThat(e).hasMessageThat().isEqualTo("type must not be null");
   }
 
   @Test
@@ -287,13 +283,9 @@ public void testNewJsonWriter_Default() throws IOException {
     jsonWriter.value(true);
     jsonWriter.endObject();
 
-    try {
-      // Additional top-level value
-      jsonWriter.value(1);
-      fail();
-    } catch (IllegalStateException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo("JSON must have only one top-level value.");
-    }
+    // Additional top-level value
+    IllegalStateException e = assertThrows(IllegalStateException.class, () -> jsonWriter.value(1));
+    assertThat(e).hasMessageThat().isEqualTo("JSON must have only one top-level value.");
 
     jsonWriter.close();
     assertThat(writer.toString()).isEqualTo("{\"\\u003ctest2\":true}");
@@ -329,11 +321,7 @@ public void testNewJsonWriter_Custom() throws IOException {
   public void testNewJsonReader_Default() throws IOException {
     String json = "test"; // String without quotes
     JsonReader jsonReader = new Gson().newJsonReader(new StringReader(json));
-    try {
-      jsonReader.nextString();
-      fail();
-    } catch (MalformedJsonException expected) {
-    }
+    assertThrows(MalformedJsonException.class, jsonReader::nextString);
     jsonReader.close();
   }
 
diff --git a/gson/src/test/java/com/google/gson/JsonArrayAsListTest.java b/gson/src/test/java/com/google/gson/JsonArrayAsListTest.java
index 4998737931..99ffaef76d 100644
--- a/gson/src/test/java/com/google/gson/JsonArrayAsListTest.java
+++ b/gson/src/test/java/com/google/gson/JsonArrayAsListTest.java
@@ -17,7 +17,7 @@
 package com.google.gson;
 
 import static com.google.common.truth.Truth.assertThat;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.assertThrows;
 
 import com.google.gson.common.MoreAsserts;
 import java.util.Arrays;
@@ -37,17 +37,8 @@ public void testGet() {
     List<JsonElement> list = a.asList();
     assertThat(list.get(0)).isEqualTo(new JsonPrimitive(1));
 
-    try {
-      list.get(-1);
-      fail();
-    } catch (IndexOutOfBoundsException e) {
-    }
-
-    try {
-      list.get(2);
-      fail();
-    } catch (IndexOutOfBoundsException e) {
-    }
+    assertThrows(IndexOutOfBoundsException.class, () -> list.get(-1));
+    assertThrows(IndexOutOfBoundsException.class, () -> list.get(2));
 
     a.add((JsonElement) null);
     assertThat(list.get(1)).isEqualTo(JsonNull.INSTANCE);
@@ -75,24 +66,11 @@ public void testSet() {
     assertThat(list.get(0)).isEqualTo(new JsonPrimitive(2));
     assertThat(a.get(0)).isEqualTo(new JsonPrimitive(2));
 
-    try {
-      list.set(-1, new JsonPrimitive(1));
-      fail();
-    } catch (IndexOutOfBoundsException e) {
-    }
-
-    try {
-      list.set(2, new JsonPrimitive(1));
-      fail();
-    } catch (IndexOutOfBoundsException e) {
-    }
-
-    try {
-      list.set(0, null);
-      fail();
-    } catch (NullPointerException e) {
-      assertThat(e).hasMessageThat().isEqualTo("Element must be non-null");
-    }
+    assertThrows(IndexOutOfBoundsException.class, () -> list.set(-1, new JsonPrimitive(1)));
+    assertThrows(IndexOutOfBoundsException.class, () -> list.set(2, new JsonPrimitive(1)));
+
+    NullPointerException e = assertThrows(NullPointerException.class, () -> list.set(0, null));
+    assertThat(e).hasMessageThat().isEqualTo("Element must be non-null");
   }
 
   @Test
@@ -115,30 +93,14 @@ public void testAdd() {
     );
     assertThat(list).isEqualTo(expectedList);
 
-    try {
-      list.set(-1, new JsonPrimitive(1));
-      fail();
-    } catch (IndexOutOfBoundsException e) {
-    }
-
-    try {
-      list.set(list.size(), new JsonPrimitive(1));
-      fail();
-    } catch (IndexOutOfBoundsException e) {
-    }
-
-    try {
-      list.add(0, null);
-      fail();
-    } catch (NullPointerException e) {
-      assertThat(e).hasMessageThat().isEqualTo("Element must be non-null");
-    }
-    try {
-      list.add(null);
-      fail();
-    } catch (NullPointerException e) {
-      assertThat(e).hasMessageThat().isEqualTo("Element must be non-null");
-    }
+    assertThrows(IndexOutOfBoundsException.class, () -> list.set(-1, new JsonPrimitive(1)));
+    assertThrows(IndexOutOfBoundsException.class, () -> list.set(list.size(), new JsonPrimitive(1)));
+
+    NullPointerException e = assertThrows(NullPointerException.class, () -> list.add(0, null));
+    assertThat(e).hasMessageThat().isEqualTo("Element must be non-null");
+
+    e = assertThrows(NullPointerException.class, () -> list.add(null));
+    assertThat(e).hasMessageThat().isEqualTo("Element must be non-null");
   }
 
   @Test
@@ -157,18 +119,11 @@ public void testAddAll() {
     assertThat(list).isEqualTo(expectedList);
     assertThat(list).isEqualTo(expectedList);
 
-    try {
-      list.addAll(0, Collections.<JsonElement>singletonList(null));
-      fail();
-    } catch (NullPointerException e) {
-      assertThat(e).hasMessageThat().isEqualTo("Element must be non-null");
-    }
-    try {
-      list.addAll(Collections.<JsonElement>singletonList(null));
-      fail();
-    } catch (NullPointerException e) {
-      assertThat(e).hasMessageThat().isEqualTo("Element must be non-null");
-    }
+    NullPointerException e = assertThrows(NullPointerException.class, () -> list.addAll(0, Collections.<JsonElement>singletonList(null)));
+    assertThat(e).hasMessageThat().isEqualTo("Element must be non-null");
+
+    e = assertThrows(NullPointerException.class, () -> list.addAll(Collections.<JsonElement>singletonList(null)));
+    assertThat(e).hasMessageThat().isEqualTo("Element must be non-null");
   }
 
   @Test
@@ -180,11 +135,8 @@ public void testRemoveIndex() {
     assertThat(list.remove(0)).isEqualTo(new JsonPrimitive(1));
     assertThat(list).hasSize(0);
     assertThat(a).hasSize(0);
-    try {
-      list.remove(0);
-      fail();
-    } catch (IndexOutOfBoundsException e) {
-    }
+
+    assertThrows(IndexOutOfBoundsException.class, () -> list.remove(0));
   }
 
   @Test
diff --git a/gson/src/test/java/com/google/gson/JsonParserTest.java b/gson/src/test/java/com/google/gson/JsonParserTest.java
index 37ba3f1375..7c9f360264 100644
--- a/gson/src/test/java/com/google/gson/JsonParserTest.java
+++ b/gson/src/test/java/com/google/gson/JsonParserTest.java
@@ -17,7 +17,7 @@
 package com.google.gson;
 
 import static com.google.common.truth.Truth.assertThat;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.assertThrows;
 
 import com.google.gson.common.TestTypes.BagOfPrimitives;
 import com.google.gson.internal.Streams;
@@ -37,10 +37,7 @@ public class JsonParserTest {
 
   @Test
   public void testParseInvalidJson() {
-    try {
-      JsonParser.parseString("[[]");
-      fail();
-    } catch (JsonSyntaxException expected) { }
+    assertThrows(JsonSyntaxException.class, () -> JsonParser.parseString("[[]"));
   }
 
   @Test
@@ -81,11 +78,7 @@ public void testParseUnquotedSingleWordStringFails() {
 
   @Test
   public void testParseUnquotedMultiWordStringFails() {
-    String unquotedSentence = "Test is a test..blah blah";
-    try {
-      JsonParser.parseString(unquotedSentence);
-      fail();
-    } catch (JsonSyntaxException expected) { }
+    assertThrows(JsonSyntaxException.class, () -> JsonParser.parseString("Test is a test..blah blah"));
   }
 
   @Test
diff --git a/gson/src/test/java/com/google/gson/JsonStreamParserTest.java b/gson/src/test/java/com/google/gson/JsonStreamParserTest.java
index 2fec1f1767..807b93f89d 100644
--- a/gson/src/test/java/com/google/gson/JsonStreamParserTest.java
+++ b/gson/src/test/java/com/google/gson/JsonStreamParserTest.java
@@ -16,7 +16,7 @@
 package com.google.gson;
 
 import static com.google.common.truth.Truth.assertThat;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.assertThrows;
 
 import java.io.EOFException;
 import java.util.NoSuchElementException;
@@ -72,57 +72,34 @@ public void testNoSideEffectForHasNext() {
   public void testCallingNextBeyondAvailableInput() {
     JsonElement unused1 = parser.next();
     JsonElement unused2 = parser.next();
-    try {
-      parser.next();
-      fail("Parser should not go beyond available input");
-    } catch (NoSuchElementException expected) {
-    }
+    // Parser should not go beyond available input
+    assertThrows(NoSuchElementException.class, parser::next);
   }
 
   @Test
   public void testEmptyInput() {
     JsonStreamParser parser = new JsonStreamParser("");
-    try {
-      parser.next();
-      fail();
-    } catch (JsonIOException e) {
-      assertThat(e.getCause()).isInstanceOf(EOFException.class);
-    }
+    JsonIOException e = assertThrows(JsonIOException.class, parser::next);
+    assertThat(e).hasCauseThat().isInstanceOf(EOFException.class);
 
     parser = new JsonStreamParser("");
-    try {
-      parser.hasNext();
-      fail();
-    } catch (JsonIOException e) {
-      assertThat(e.getCause()).isInstanceOf(EOFException.class);
-    }
+    e = assertThrows(JsonIOException.class, parser::hasNext);
+    assertThat(e).hasCauseThat().isInstanceOf(EOFException.class);
   }
 
   @Test
   public void testIncompleteInput() {
     JsonStreamParser parser = new JsonStreamParser("[");
     assertThat(parser.hasNext()).isTrue();
-    try {
-      parser.next();
-      fail();
-    } catch (JsonSyntaxException e) {
-    }
+    assertThrows(JsonSyntaxException.class, parser::next);
   }
 
   @Test
   public void testMalformedInput() {
     JsonStreamParser parser = new JsonStreamParser(":");
-    try {
-      parser.hasNext();
-      fail();
-    } catch (JsonSyntaxException e) {
-    }
+    assertThrows(JsonSyntaxException.class, parser::hasNext);
 
     parser = new JsonStreamParser(":");
-    try {
-      parser.next();
-      fail();
-    } catch (JsonSyntaxException e) {
-    }
+    assertThrows(JsonSyntaxException.class, parser::next);
   }
 }
diff --git a/gson/src/test/java/com/google/gson/ToNumberPolicyTest.java b/gson/src/test/java/com/google/gson/ToNumberPolicyTest.java
index 014be170a6..50a85441b6 100644
--- a/gson/src/test/java/com/google/gson/ToNumberPolicyTest.java
+++ b/gson/src/test/java/com/google/gson/ToNumberPolicyTest.java
@@ -17,7 +17,7 @@
 package com.google.gson;
 
 import static com.google.common.truth.Truth.assertThat;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.assertThrows;
 
 import com.google.gson.internal.LazilyParsedNumber;
 import com.google.gson.stream.JsonReader;
@@ -33,19 +33,14 @@ public void testDouble() throws IOException {
     ToNumberStrategy strategy = ToNumberPolicy.DOUBLE;
     assertThat(strategy.readNumber(fromString("10.1"))).isEqualTo(10.1);
     assertThat(strategy.readNumber(fromString("3.141592653589793238462643383279"))).isEqualTo(3.141592653589793D);
-    try {
-      strategy.readNumber(fromString("1e400"));
-      fail();
-    } catch (MalformedJsonException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo(
-          "JSON forbids NaN and infinities: Infinity at line 1 column 6 path $"
-          + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#malformed-json");
-    }
-    try {
-      strategy.readNumber(fromString("\"not-a-number\""));
-      fail();
-    } catch (NumberFormatException expected) {
-    }
+
+    MalformedJsonException e = assertThrows(MalformedJsonException.class, () -> strategy.readNumber(fromString("1e400")));
+    assertThat(e).hasMessageThat().isEqualTo(
+        "JSON forbids NaN and infinities: Infinity at line 1 column 6 path $"
+        + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#malformed-json"
+    );
+
+    assertThrows(NumberFormatException.class, () -> strategy.readNumber(fromString("\"not-a-number\"")));
   }
 
   @Test
@@ -62,46 +57,31 @@ public void testLongOrDouble() throws IOException {
     assertThat(strategy.readNumber(fromString("10"))).isEqualTo(10L);
     assertThat(strategy.readNumber(fromString("10.1"))).isEqualTo(10.1);
     assertThat(strategy.readNumber(fromString("3.141592653589793238462643383279"))).isEqualTo(3.141592653589793D);
-    try {
-      strategy.readNumber(fromString("1e400"));
-      fail();
-    } catch (MalformedJsonException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo("JSON forbids NaN and infinities: Infinity; at path $");
-    }
-    try {
-      strategy.readNumber(fromString("\"not-a-number\""));
-      fail();
-    } catch (JsonParseException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo("Cannot parse not-a-number; at path $");
-    }
+
+    Exception e = assertThrows(MalformedJsonException.class, () -> strategy.readNumber(fromString("1e400")));
+    assertThat(e).hasMessageThat().isEqualTo("JSON forbids NaN and infinities: Infinity; at path $");
+
+    e = assertThrows(JsonParseException.class, () -> strategy.readNumber(fromString("\"not-a-number\"")));
+    assertThat(e).hasMessageThat().isEqualTo("Cannot parse not-a-number; at path $");
 
     assertThat(strategy.readNumber(fromStringLenient("NaN"))).isEqualTo(Double.NaN);
     assertThat(strategy.readNumber(fromStringLenient("Infinity"))).isEqualTo(Double.POSITIVE_INFINITY);
     assertThat(strategy.readNumber(fromStringLenient("-Infinity"))).isEqualTo(Double.NEGATIVE_INFINITY);
-    try {
-      strategy.readNumber(fromString("NaN"));
-      fail();
-    } catch (MalformedJsonException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo(
-          "Use JsonReader.setStrictness(Strictness.LENIENT) to accept malformed JSON at line 1 column 1 path $"
-          + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#malformed-json");
-    }
-    try {
-      strategy.readNumber(fromString("Infinity"));
-      fail();
-    } catch (MalformedJsonException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo(
-          "Use JsonReader.setStrictness(Strictness.LENIENT) to accept malformed JSON at line 1 column 1 path $"
-          + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#malformed-json");
-    }
-    try {
-      strategy.readNumber(fromString("-Infinity"));
-      fail();
-    } catch (MalformedJsonException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo(
-          "Use JsonReader.setStrictness(Strictness.LENIENT) to accept malformed JSON at line 1 column 1 path $"
-          + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#malformed-json");
-    }
+
+    e = assertThrows(MalformedJsonException.class, () -> strategy.readNumber(fromString("NaN")));
+    assertThat(e).hasMessageThat().isEqualTo(
+        "Use JsonReader.setStrictness(Strictness.LENIENT) to accept malformed JSON at line 1 column 1 path $"
+        + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#malformed-json");
+
+    e = assertThrows(MalformedJsonException.class, () -> strategy.readNumber(fromString("Infinity")));
+    assertThat(e).hasMessageThat().isEqualTo(
+        "Use JsonReader.setStrictness(Strictness.LENIENT) to accept malformed JSON at line 1 column 1 path $"
+        + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#malformed-json");
+
+    e = assertThrows(MalformedJsonException.class, () -> strategy.readNumber(fromString("-Infinity")));
+    assertThat(e).hasMessageThat().isEqualTo(
+        "Use JsonReader.setStrictness(Strictness.LENIENT) to accept malformed JSON at line 1 column 1 path $"
+        + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#malformed-json");
   }
 
   @Test
@@ -111,44 +91,27 @@ public void testBigDecimal() throws IOException {
     assertThat(strategy.readNumber(fromString("3.141592653589793238462643383279"))).isEqualTo(new BigDecimal("3.141592653589793238462643383279"));
     assertThat(strategy.readNumber(fromString("1e400"))).isEqualTo(new BigDecimal("1e400"));
 
-    try {
-      strategy.readNumber(fromString("\"not-a-number\""));
-      fail();
-    } catch (JsonParseException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo("Cannot parse not-a-number; at path $");
-    }
+    JsonParseException e = assertThrows(JsonParseException.class, () -> strategy.readNumber(fromString("\"not-a-number\"")));
+    assertThat(e).hasMessageThat().isEqualTo("Cannot parse not-a-number; at path $");
   }
 
   @Test
   public void testNullsAreNeverExpected() throws IOException {
-    try {
-      ToNumberPolicy.DOUBLE.readNumber(fromString("null"));
-      fail();
-    } catch (IllegalStateException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo("Expected a double but was NULL at line 1 column 5 path $"
-          + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#adapter-not-null-safe");
-    }
-    try {
-      ToNumberPolicy.LAZILY_PARSED_NUMBER.readNumber(fromString("null"));
-      fail();
-    } catch (IllegalStateException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo("Expected a string but was NULL at line 1 column 5 path $"
-          + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#adapter-not-null-safe");
-    }
-    try {
-      ToNumberPolicy.LONG_OR_DOUBLE.readNumber(fromString("null"));
-      fail();
-    } catch (IllegalStateException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo("Expected a string but was NULL at line 1 column 5 path $"
-          + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#adapter-not-null-safe");
-    }
-    try {
-      ToNumberPolicy.BIG_DECIMAL.readNumber(fromString("null"));
-      fail();
-    } catch (IllegalStateException expected) {
-      assertThat(expected).hasMessageThat().isEqualTo("Expected a string but was NULL at line 1 column 5 path $"
-          + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#adapter-not-null-safe");
-    }
+    IllegalStateException e = assertThrows(IllegalStateException.class, () -> ToNumberPolicy.DOUBLE.readNumber(fromString("null")));
+    assertThat(e).hasMessageThat().isEqualTo("Expected a double but was NULL at line 1 column 5 path $"
+        + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#adapter-not-null-safe");
+
+    e = assertThrows(IllegalStateException.class, () -> ToNumberPolicy.LAZILY_PARSED_NUMBER.readNumber(fromString("null")));
+    assertThat(e).hasMessageThat().isEqualTo("Expected a string but was NULL at line 1 column 5 path $"
+        + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#adapter-not-null-safe");
+
+    e = assertThrows(IllegalStateException.class, () -> ToNumberPolicy.LONG_OR_DOUBLE.readNumber(fromString("null")));
+    assertThat(e).hasMessageThat().isEqualTo("Expected a string but was NULL at line 1 column 5 path $"
+        + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#adapter-not-null-safe");
+
+    e = assertThrows(IllegalStateException.class, () -> ToNumberPolicy.BIG_DECIMAL.readNumber(fromString("null")));
+    assertThat(e).hasMessageThat().isEqualTo("Expected a string but was NULL at line 1 column 5 path $"
+        + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#adapter-not-null-safe");
   }
 
   private static JsonReader fromString(String json) {
diff --git a/gson/src/test/java/com/google/gson/TypeAdapterTest.java b/gson/src/test/java/com/google/gson/TypeAdapterTest.java
index 18af4c4bfa..ea3042eb08 100644
--- a/gson/src/test/java/com/google/gson/TypeAdapterTest.java
+++ b/gson/src/test/java/com/google/gson/TypeAdapterTest.java
@@ -17,7 +17,7 @@
 package com.google.gson;
 
 import static com.google.common.truth.Truth.assertThat;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.assertThrows;
 
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
@@ -59,19 +59,11 @@ public void testToJson_ThrowingIOException() {
       }
     };
 
-    try {
-      adapter.toJson(1);
-      fail();
-    } catch (JsonIOException e) {
-      assertThat(e.getCause()).isEqualTo(exception);
-    }
+    JsonIOException e = assertThrows(JsonIOException.class, () -> adapter.toJson(1));
+    assertThat(e).hasCauseThat().isEqualTo(exception);
 
-    try {
-      adapter.toJsonTree(1);
-      fail();
-    } catch (JsonIOException e) {
-      assertThat(e.getCause()).isEqualTo(exception);
-    }
+    e = assertThrows(JsonIOException.class, () -> adapter.toJsonTree(1));
+    assertThat(e).hasCauseThat().isEqualTo(exception);
   }
 
   private static final TypeAdapter<String> adapter = new TypeAdapter<String>() {
diff --git a/gson/src/test/java/com/google/gson/functional/DefaultTypeAdaptersTest.java b/gson/src/test/java/com/google/gson/functional/DefaultTypeAdaptersTest.java
index e70c175b3c..e858062dd1 100644
--- a/gson/src/test/java/com/google/gson/functional/DefaultTypeAdaptersTest.java
+++ b/gson/src/test/java/com/google/gson/functional/DefaultTypeAdaptersTest.java
@@ -384,11 +384,7 @@ public void testBitSetDeserialization() {
   public void testDefaultDateSerialization() {
     Date now = new Date(1315806903103L);
     String json = gson.toJson(now);
-    if (JavaVersion.isJava9OrLater()) {
-      assertThat(json).isEqualTo("\"Sep 11, 2011, 10:55:03 PM\"");
-    } else {
-      assertThat(json).isEqualTo("\"Sep 11, 2011 10:55:03 PM\"");
-    }
+    assertThat(json).matches("\"Sep 11, 2011,? 10:55:03\\hPM\"");
   }
 
   @Test
@@ -420,11 +416,7 @@ public void testDefaultDateSerializationUsingBuilder() {
     Gson gson = new GsonBuilder().create();
     Date now = new Date(1315806903103L);
     String json = gson.toJson(now);
-    if (JavaVersion.isJava9OrLater()) {
-      assertThat(json).isEqualTo("\"Sep 11, 2011, 10:55:03 PM\"");
-    } else {
-      assertThat(json).isEqualTo("\"Sep 11, 2011 10:55:03 PM\"");
-    }
+    assertThat(json).matches("\"Sep 11, 2011,? 10:55:03\\hPM\"");
   }
 
   @Test
diff --git a/gson/src/test/java/com/google/gson/functional/Java17RecordTest.java b/gson/src/test/java/com/google/gson/functional/Java17RecordTest.java
index 0b9a6c078c..bc9e8f06b6 100644
--- a/gson/src/test/java/com/google/gson/functional/Java17RecordTest.java
+++ b/gson/src/test/java/com/google/gson/functional/Java17RecordTest.java
@@ -89,7 +89,7 @@ public int i() {
 
     var exception = assertThrows(JsonIOException.class, () -> gson.getAdapter(LocalRecord.class));
     assertThat(exception).hasMessageThat()
-            .isEqualTo("@SerializedName on method '" + LocalRecord.class.getName() + "#i()' is not supported");
+        .isEqualTo("@SerializedName on method '" + LocalRecord.class.getName() + "#i()' is not supported");
   }
 
   @Test
@@ -154,7 +154,7 @@ record LocalRecord(String s) {
     // TODO: Adjust this once Gson throws more specific exception type
     catch (RuntimeException e) {
       assertThat(e).hasMessageThat()
-              .isEqualTo("Failed to invoke constructor '" + LocalRecord.class.getName() + "(String)' with args [value]");
+          .isEqualTo("Failed to invoke constructor '" + LocalRecord.class.getName() + "(String)' with args [value]");
       assertThat(e).hasCauseThat().isSameInstanceAs(LocalRecord.thrownException);
     }
   }
@@ -227,7 +227,7 @@ public void testPrimitiveJsonNullValue() {
     String s = "{'aString': 's', 'aByte': null, 'aShort': 0}";
     var e = assertThrows(JsonParseException.class, () -> gson.fromJson(s, RecordWithPrimitives.class));
     assertThat(e).hasMessageThat()
-            .isEqualTo("null is not allowed as value for record component 'aByte' of primitive type; at path $.aByte");
+        .isEqualTo("null is not allowed as value for record component 'aByte' of primitive type; at path $.aByte");
   }
 
   /**
@@ -384,8 +384,8 @@ record Blocked(int b) {}
 
     var exception = assertThrows(JsonIOException.class, () -> gson.toJson(new Blocked(1)));
     assertThat(exception).hasMessageThat()
-            .isEqualTo("ReflectionAccessFilter does not permit using reflection for class " + Blocked.class.getName() +
-                ". Register a TypeAdapter for this type or adjust the access filter.");
+        .isEqualTo("ReflectionAccessFilter does not permit using reflection for class " + Blocked.class.getName() +
+            ". Register a TypeAdapter for this type or adjust the access filter.");
   }
 
   @Test
@@ -396,15 +396,15 @@ public void testReflectionFilterBlockInaccessible() {
 
     var exception = assertThrows(JsonIOException.class, () -> gson.toJson(new PrivateRecord(1)));
     assertThat(exception).hasMessageThat()
-            .isEqualTo("Constructor 'com.google.gson.functional.Java17RecordTest$PrivateRecord(int)' is not accessible and"
-                + " ReflectionAccessFilter does not permit making it accessible. Register a TypeAdapter for the declaring"
-                + " type, adjust the access filter or increase the visibility of the element and its declaring type.");
+        .isEqualTo("Constructor 'com.google.gson.functional.Java17RecordTest$PrivateRecord(int)' is not accessible and"
+            + " ReflectionAccessFilter does not permit making it accessible. Register a TypeAdapter for the declaring"
+            + " type, adjust the access filter or increase the visibility of the element and its declaring type.");
 
     exception = assertThrows(JsonIOException.class, () -> gson.fromJson("{}", PrivateRecord.class));
     assertThat(exception).hasMessageThat()
-            .isEqualTo("Constructor 'com.google.gson.functional.Java17RecordTest$PrivateRecord(int)' is not accessible and"
-                + " ReflectionAccessFilter does not permit making it accessible. Register a TypeAdapter for the declaring"
-                + " type, adjust the access filter or increase the visibility of the element and its declaring type.");
+        .isEqualTo("Constructor 'com.google.gson.functional.Java17RecordTest$PrivateRecord(int)' is not accessible and"
+            + " ReflectionAccessFilter does not permit making it accessible. Register a TypeAdapter for the declaring"
+            + " type, adjust the access filter or increase the visibility of the element and its declaring type.");
 
     assertThat(gson.toJson(new PublicRecord(1))).isEqualTo("{\"i\":1}");
     assertThat(gson.fromJson("{\"i\":2}", PublicRecord.class)).isEqualTo(new PublicRecord(2));
@@ -427,7 +427,8 @@ record LocalRecord(int i) {}
 
     var exception = assertThrows(JsonIOException.class, () -> gson.fromJson("{}", Record.class));
     assertThat(exception).hasMessageThat()
-            .isEqualTo("Abstract classes can't be instantiated! Register an InstanceCreator or a TypeAdapter for"
-                + " this type. Class name: java.lang.Record");
+        .isEqualTo("Abstract classes can't be instantiated! Adjust the R8 configuration or register an InstanceCreator"
+            + " or a TypeAdapter for this type. Class name: java.lang.Record"
+            + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#r8-abstract-class");
   }
 }
diff --git a/gson/src/test/java/com/google/gson/functional/ObjectTest.java b/gson/src/test/java/com/google/gson/functional/ObjectTest.java
index b0de9da48d..e0efd94dee 100644
--- a/gson/src/test/java/com/google/gson/functional/ObjectTest.java
+++ b/gson/src/test/java/com/google/gson/functional/ObjectTest.java
@@ -570,11 +570,8 @@ static final class Product {
   public void testDateAsMapObjectField() {
     HasObjectMap a = new HasObjectMap();
     a.map.put("date", new Date(0));
-    if (JavaVersion.isJava9OrLater()) {
-      assertThat(gson.toJson(a)).isEqualTo("{\"map\":{\"date\":\"Dec 31, 1969, 4:00:00 PM\"}}");
-    } else {
-      assertThat(gson.toJson(a)).isEqualTo("{\"map\":{\"date\":\"Dec 31, 1969 4:00:00 PM\"}}");
-    }
+    assertThat(gson.toJson(a))
+        .matches("\\{\"map\":\\{\"date\":\"Dec 31, 1969,? 4:00:00\\hPM\"\\}\\}");
   }
 
   static class HasObjectMap {
diff --git a/gson/src/test/java/com/google/gson/internal/ConstructorConstructorTest.java b/gson/src/test/java/com/google/gson/internal/ConstructorConstructorTest.java
index 602ba074e9..e582ad08ac 100644
--- a/gson/src/test/java/com/google/gson/internal/ConstructorConstructorTest.java
+++ b/gson/src/test/java/com/google/gson/internal/ConstructorConstructorTest.java
@@ -19,17 +19,14 @@
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.fail;
 
-import com.google.gson.InstanceCreator;
-import com.google.gson.ReflectionAccessFilter;
 import com.google.gson.reflect.TypeToken;
-import java.lang.reflect.Type;
 import java.util.Collections;
 import org.junit.Test;
 
 public class ConstructorConstructorTest {
   private ConstructorConstructor constructorConstructor = new ConstructorConstructor(
-      Collections.<Type, InstanceCreator<?>>emptyMap(), true,
-      Collections.<ReflectionAccessFilter>emptyList()
+      Collections.emptyMap(), true,
+      Collections.emptyList()
   );
 
   private abstract static class AbstractClass {
@@ -39,7 +36,7 @@ public AbstractClass() { }
   private interface Interface { }
 
   /**
-   * Verify that ConstructorConstructor does not try to invoke no-arg constructor
+   * Verify that ConstructorConstructor does not try to invoke no-args constructor
    * of abstract class.
    */
   @Test
@@ -49,9 +46,10 @@ public void testGet_AbstractClassNoArgConstructor() {
       constructor.construct();
       fail("Expected exception");
     } catch (RuntimeException exception) {
-      assertThat(exception).hasMessageThat().isEqualTo("Abstract classes can't be instantiated! "
-          + "Register an InstanceCreator or a TypeAdapter for this type. "
-          + "Class name: com.google.gson.internal.ConstructorConstructorTest$AbstractClass");
+      assertThat(exception).hasMessageThat().isEqualTo("Abstract classes can't be instantiated!"
+          + " Adjust the R8 configuration or register an InstanceCreator or a TypeAdapter for this type."
+          + " Class name: com.google.gson.internal.ConstructorConstructorTest$AbstractClass"
+          + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#r8-abstract-class");
     }
   }
 
@@ -62,9 +60,9 @@ public void testGet_Interface() {
       constructor.construct();
       fail("Expected exception");
     } catch (RuntimeException exception) {
-      assertThat(exception).hasMessageThat().isEqualTo("Interfaces can't be instantiated! "
-          + "Register an InstanceCreator or a TypeAdapter for this type. "
-          + "Interface name: com.google.gson.internal.ConstructorConstructorTest$Interface");
+      assertThat(exception).hasMessageThat().isEqualTo("Interfaces can't be instantiated!"
+          + " Register an InstanceCreator or a TypeAdapter for this type."
+          + " Interface name: com.google.gson.internal.ConstructorConstructorTest$Interface");
     }
   }
 }
diff --git a/gson/src/test/java/com/google/gson/internal/bind/DefaultDateTypeAdapterTest.java b/gson/src/test/java/com/google/gson/internal/bind/DefaultDateTypeAdapterTest.java
index 2034e38fc6..835bc9dd49 100644
--- a/gson/src/test/java/com/google/gson/internal/bind/DefaultDateTypeAdapterTest.java
+++ b/gson/src/test/java/com/google/gson/internal/bind/DefaultDateTypeAdapterTest.java
@@ -58,21 +58,22 @@ private void assertFormattingAlwaysEmitsUsLocale(Locale locale) {
     Locale defaultLocale = Locale.getDefault();
     Locale.setDefault(locale);
     try {
-      String afterYearSep = JavaVersion.isJava9OrLater() ? ", " : " ";
-      String afterYearLongSep = JavaVersion.isJava9OrLater() ? " at " : " ";
-      String utcFull = JavaVersion.isJava9OrLater() ? "Coordinated Universal Time" : "UTC";
-      assertFormatted(String.format("Jan 1, 1970%s12:00:00 AM", afterYearSep),
-          DateType.DATE.createDefaultsAdapterFactory());
+      // The patterns here attempt to accommodate minor date-time formatting differences between JDK
+      // versions. Ideally Gson would serialize in a way that is independent of the JDK version.
+      // Note: \h means "horizontal space", because some JDK versions use Narrow No Break Space
+      // (U+202F) before the AM or PM indication.
+      String utcFull = "(Coordinated Universal Time|UTC)";
+      assertFormatted("Jan 1, 1970,? 12:00:00\\hAM", DateType.DATE.createDefaultsAdapterFactory());
       assertFormatted("1/1/70", DateType.DATE.createAdapterFactory(DateFormat.SHORT));
       assertFormatted("Jan 1, 1970", DateType.DATE.createAdapterFactory(DateFormat.MEDIUM));
       assertFormatted("January 1, 1970", DateType.DATE.createAdapterFactory(DateFormat.LONG));
-      assertFormatted(String.format("1/1/70%s12:00 AM", afterYearSep),
+      assertFormatted("1/1/70,? 12:00\\hAM",
           DateType.DATE.createAdapterFactory(DateFormat.SHORT, DateFormat.SHORT));
-      assertFormatted(String.format("Jan 1, 1970%s12:00:00 AM", afterYearSep),
+      assertFormatted("Jan 1, 1970,? 12:00:00\\hAM",
           DateType.DATE.createAdapterFactory(DateFormat.MEDIUM, DateFormat.MEDIUM));
-      assertFormatted(String.format("January 1, 1970%s12:00:00 AM UTC", afterYearLongSep),
+      assertFormatted("January 1, 1970(,| at)? 12:00:00\\hAM UTC",
           DateType.DATE.createAdapterFactory(DateFormat.LONG, DateFormat.LONG));
-      assertFormatted(String.format("Thursday, January 1, 1970%s12:00:00 AM %s", afterYearLongSep, utcFull),
+      assertFormatted("Thursday, January 1, 1970(,| at)? 12:00:00\\hAM " + utcFull,
           DateType.DATE.createAdapterFactory(DateFormat.FULL, DateFormat.FULL));
     } finally {
       TimeZone.setDefault(defaultTimeZone);
@@ -150,9 +151,7 @@ public void testFormatUsesDefaultTimezone() throws Exception {
     Locale defaultLocale = Locale.getDefault();
     Locale.setDefault(Locale.US);
     try {
-      String afterYearSep = JavaVersion.isJava9OrLater() ? ", " : " ";
-      assertFormatted(String.format("Dec 31, 1969%s4:00:00 PM", afterYearSep),
-          DateType.DATE.createDefaultsAdapterFactory());
+      assertFormatted("Dec 31, 1969,? 4:00:00\\hPM", DateType.DATE.createDefaultsAdapterFactory());
       assertParsed("Dec 31, 1969 4:00:00 PM", DateType.DATE.createDefaultsAdapterFactory());
     } finally {
       TimeZone.setDefault(defaultTimeZone);
@@ -222,9 +221,10 @@ private static TypeAdapter<Date> dateAdapter(TypeAdapterFactory adapterFactory)
     return adapter;
   }
 
-  private static void assertFormatted(String formatted, TypeAdapterFactory adapterFactory) {
+  private static void assertFormatted(String formattedPattern, TypeAdapterFactory adapterFactory) {
     TypeAdapter<Date> adapter = dateAdapter(adapterFactory);
-    assertThat(adapter.toJson(new Date(0))).isEqualTo(toLiteral(formatted));
+    String json = adapter.toJson(new Date(0));
+    assertThat(json).matches(toLiteral(formattedPattern));
   }
 
   @SuppressWarnings("UndefinedEquals")
diff --git a/gson/src/test/java/com/google/gson/internal/sql/SqlTypesGsonTest.java b/gson/src/test/java/com/google/gson/internal/sql/SqlTypesGsonTest.java
index b04c56ab34..8233275c37 100644
--- a/gson/src/test/java/com/google/gson/internal/sql/SqlTypesGsonTest.java
+++ b/gson/src/test/java/com/google/gson/internal/sql/SqlTypesGsonTest.java
@@ -113,11 +113,10 @@ public void testDefaultSqlTimeDeserialization() {
   public void testDefaultSqlTimestampSerialization() {
     Timestamp now = new java.sql.Timestamp(1259875082000L);
     String json = gson.toJson(now);
-    if (JavaVersion.isJava9OrLater()) {
-      assertThat(json).isEqualTo("\"Dec 3, 2009, 1:18:02 PM\"");
-    } else {
-      assertThat(json).isEqualTo("\"Dec 3, 2009 1:18:02 PM\"");
-    }
+    // The exact format of the serialized date-time string depends on the JDK version. The pattern
+    // here allows for an optional comma after the date, and what might be U+202F (Narrow No-Break
+    // Space) before "PM".
+    assertThat(json).matches("\"Dec 3, 2009,? 1:18:02\\hPM\"");
   }
 
   @Test
diff --git a/gson/src/test/java/com/google/gson/reflect/TypeTokenTest.java b/gson/src/test/java/com/google/gson/reflect/TypeTokenTest.java
index d38f05b1ec..4c1ccf0d6b 100644
--- a/gson/src/test/java/com/google/gson/reflect/TypeTokenTest.java
+++ b/gson/src/test/java/com/google/gson/reflect/TypeTokenTest.java
@@ -146,6 +146,9 @@ public void testParameterizedFactory() {
     class LocalGenericClass<T> {}
     TypeToken<?> expectedLocalType = new TypeToken<LocalGenericClass<Integer>>() {};
     assertThat(TypeToken.getParameterized(LocalGenericClass.class, Integer.class)).isEqualTo(expectedLocalType);
+
+    // For legacy reasons, if requesting parameterized type for non-generic class, create a `TypeToken(Class)`
+    assertThat(TypeToken.getParameterized(String.class)).isEqualTo(TypeToken.get(String.class));
   }
 
   @Test
@@ -158,7 +161,7 @@ public void testParameterizedFactory_Invalid() {
     assertThat(e).hasMessageThat().isEqualTo("rawType must be of type Class, but was java.lang.String[]");
 
     e = assertThrows(IllegalArgumentException.class, () -> TypeToken.getParameterized(String.class, Number.class));
-    assertThat(e).hasMessageThat().isEqualTo("java.lang.String is not a generic type");
+    assertThat(e).hasMessageThat().isEqualTo("java.lang.String requires 0 type arguments, but got 1");
 
     e = assertThrows(IllegalArgumentException.class, () -> TypeToken.getParameterized(List.class, new Type[0]));
     assertThat(e).hasMessageThat().isEqualTo("java.util.List requires 1 type arguments, but got 0");
diff --git a/proto/pom.xml b/proto/pom.xml
index fbf87b17b0..dfd2024bf6 100644
--- a/proto/pom.xml
+++ b/proto/pom.xml
@@ -50,7 +50,7 @@
     <dependency>
       <groupId>com.google.guava</groupId>
       <artifactId>guava</artifactId>
-      <version>32.0.1-jre</version>
+      <version>32.1.1-jre</version>
     </dependency>
 
     <dependency>
diff --git a/shrinker-test/pom.xml b/shrinker-test/pom.xml
index e72d26e60d..65de7c7f12 100644
--- a/shrinker-test/pom.xml
+++ b/shrinker-test/pom.xml
@@ -199,6 +199,8 @@
         <dependencies>
           <dependency>
             <!-- R8 dependency used above -->
+            <!-- Note: For some reason Maven shows the warning "Missing POM for com.android.tools:r8:jar",
+              but it appears that can be ignored -->
             <groupId>com.android.tools</groupId>
             <artifactId>r8</artifactId>
             <version>8.0.40</version>
diff --git a/shrinker-test/proguard.pro b/shrinker-test/proguard.pro
index 0cb35048c9..3e8a812041 100644
--- a/shrinker-test/proguard.pro
+++ b/shrinker-test/proguard.pro
@@ -18,6 +18,7 @@
 -keep class com.example.DefaultConstructorMain {
   public static java.lang.String runTest();
   public static java.lang.String runTestNoJdkUnsafe();
+  public static java.lang.String runTestNoDefaultConstructor();
 }
 
 
@@ -27,3 +28,21 @@
 -keepclassmembers class com.example.ClassWithNamedFields {
   !transient <fields>;
 }
+
+-keepclassmembernames class com.example.ClassWithExposeAnnotation {
+  <fields>;
+}
+-keepclassmembernames class com.example.ClassWithJsonAdapterAnnotation {
+  ** f;
+}
+-keepclassmembernames class com.example.ClassWithVersionAnnotations {
+  <fields>;
+}
+
+
+-keepclassmembernames class com.example.DefaultConstructorMain$TestClass {
+  <fields>;
+}
+-keepclassmembernames class com.example.DefaultConstructorMain$TestClassNotAbstract {
+  <fields>;
+}
diff --git a/shrinker-test/r8.pro b/shrinker-test/r8.pro
index 690fe339b5..392f0f0d9c 100644
--- a/shrinker-test/r8.pro
+++ b/shrinker-test/r8.pro
@@ -4,20 +4,6 @@
 ### The following rules are needed for R8 in "full mode", which performs more aggressive optimizations than ProGuard
 ### See https://r8.googlesource.com/r8/+/refs/heads/main/compatibility-faq.md#r8-full-mode
 
-# Keep the no-args constructor of deserialized classes
--keepclassmembers class com.example.ClassWithDefaultConstructor {
-  <init>();
-}
--keepclassmembers class com.example.GenericClasses$GenericClass {
-  <init>();
-}
--keepclassmembers class com.example.GenericClasses$UsingGenericClass {
-  <init>();
-}
--keepclassmembers class com.example.GenericClasses$GenericUsingGenericClass {
-  <init>();
-}
-
 # For classes with generic type parameter R8 in "full mode" requires to have a keep rule to
 # preserve the generic signature
 -keep,allowshrinking,allowoptimization,allowobfuscation,allowaccessmodification class com.example.GenericClasses$GenericClass
@@ -25,12 +11,14 @@
 
 # Don't obfuscate class name, to check it in exception message
 -keep,allowshrinking,allowoptimization class com.example.DefaultConstructorMain$TestClass
+-keep,allowshrinking,allowoptimization class com.example.DefaultConstructorMain$TestClassWithoutDefaultConstructor
+
 # This rule has the side-effect that R8 still removes the no-args constructor, but does not make the class abstract
 -keep class com.example.DefaultConstructorMain$TestClassNotAbstract {
   @com.google.gson.annotations.SerializedName <fields>;
 }
 
 # Keep enum constants which are not explicitly used in code
--keep class com.example.EnumClass {
+-keepclassmembers class com.example.EnumClass {
   ** SECOND;
 }
diff --git a/shrinker-test/src/main/java/com/example/ClassWithJsonAdapterAnnotation.java b/shrinker-test/src/main/java/com/example/ClassWithJsonAdapterAnnotation.java
index 238ee1818e..0cb05a25a6 100644
--- a/shrinker-test/src/main/java/com/example/ClassWithJsonAdapterAnnotation.java
+++ b/shrinker-test/src/main/java/com/example/ClassWithJsonAdapterAnnotation.java
@@ -23,6 +23,7 @@
  */
 public class ClassWithJsonAdapterAnnotation {
   // For this field don't use @SerializedName and ignore it for deserialization
+  // Has custom ProGuard rule to keep the field name
   @JsonAdapter(value = Adapter.class, nullSafe = false)
   DummyClass f;
 
diff --git a/shrinker-test/src/main/java/com/example/DefaultConstructorMain.java b/shrinker-test/src/main/java/com/example/DefaultConstructorMain.java
index e570866bec..4f0152f7d1 100644
--- a/shrinker-test/src/main/java/com/example/DefaultConstructorMain.java
+++ b/shrinker-test/src/main/java/com/example/DefaultConstructorMain.java
@@ -8,14 +8,24 @@
 
 public class DefaultConstructorMain {
   static class TestClass {
-    @SerializedName("s")
     public String s;
   }
 
   // R8 rule for this class still removes no-args constructor, but doesn't make class abstract
   static class TestClassNotAbstract {
+    public String s;
+  }
+
+  // Current Gson ProGuard rules only keep default constructor (and only then prevent R8 from
+  // making class abstract); other constructors are ignored to suggest to user adding default
+  // constructor instead of implicitly relying on JDK Unsafe
+  static class TestClassWithoutDefaultConstructor {
     @SerializedName("s")
     public String s;
+
+    public TestClassWithoutDefaultConstructor(String s) {
+      this.s = s;
+    }
   }
 
   /**
@@ -34,4 +44,12 @@ public static String runTestNoJdkUnsafe() {
     TestClassNotAbstract deserialized = gson.fromJson("{\"s\": \"value\"}", same(TestClassNotAbstract.class));
     return deserialized.s;
   }
+
+  /**
+   * Main entrypoint, called by {@code ShrinkingIT.testNoDefaultConstructor()}.
+   */
+  public static String runTestNoDefaultConstructor() {
+    TestClassWithoutDefaultConstructor deserialized = new Gson().fromJson("{\"s\":\"value\"}", same(TestClassWithoutDefaultConstructor.class));
+    return deserialized.s;
+  }
 }
diff --git a/shrinker-test/src/test/java/com/google/gson/it/ShrinkingIT.java b/shrinker-test/src/test/java/com/google/gson/it/ShrinkingIT.java
index 9c32f1aa57..3304570197 100644
--- a/shrinker-test/src/test/java/com/google/gson/it/ShrinkingIT.java
+++ b/shrinker-test/src/test/java/com/google/gson/it/ShrinkingIT.java
@@ -220,4 +220,24 @@ public void testDefaultConstructorNoJdkUnsafe() throws Exception {
       }
     });
   }
+
+  @Test
+  public void testNoDefaultConstructor() throws Exception {
+    runTest("com.example.DefaultConstructorMain", c -> {
+      Method m = c.getMethod("runTestNoDefaultConstructor");
+
+      if (jarToTest.equals(PROGUARD_RESULT_PATH)) {
+        Object result = m.invoke(null);
+        assertThat(result).isEqualTo("value");
+      } else {
+        // R8 performs more aggressive optimizations
+        Exception e = assertThrows(InvocationTargetException.class, () -> m.invoke(null));
+        assertThat(e).hasCauseThat().hasMessageThat().isEqualTo(
+            "Abstract classes can't be instantiated! Adjust the R8 configuration or register an InstanceCreator"
+            + " or a TypeAdapter for this type. Class name: com.example.DefaultConstructorMain$TestClassWithoutDefaultConstructor"
+            + "\nSee https://github.com/google/gson/blob/main/Troubleshooting.md#r8-abstract-class"
+        );
+      }
+    });
+  }
 }