After modifying the agent code, an error occurred when building the javaagent.

[huange7]

Error msg:

LogLevelTest > SLF4J DEBUG && otel.javaagent.debug is false STANDARD_OUT
    16:22:21.400 [Thread-9] INFO  i.o.javaagent.IntegrationTestUtils - ERROR> OpenJDK 64-Bit Server VM warning: Sharing is only supported for boot loader classes because bootstrap classpath has been appended
OpenJDK 64-Bit Server VM warning: Sharing is only supported for boot loader classes because bootstrap classpath has been appended
OpenTelemetry Javaagent failed to start
java.lang.NoClassDefFoundError: io/opentelemetry/javaagent/shaded/io/opentelemetry/api/metrics/MeterProvider
	at io.opentelemetry.sdk.autoconfigure.AutoConfiguredOpenTelemetrySdk.builder(AutoConfiguredOpenTelemetrySdk.java:42)
	at io.opentelemetry.javaagent.tooling.OpenTelemetryInstaller.installOpenTelemetrySdk(OpenTelemetryInstaller.java:26)
	at io.opentelemetry.javaagent.tooling.AgentInstaller.installBytebuddyAgent(AgentInstaller.java:123)
	at io.opentelemetry.javaagent.tooling.AgentInstaller.installBytebuddyAgent(AgentInstaller.java:103)
	at io.opentelemetry.javaagent.tooling.AgentStarterImpl.start(AgentStarterImpl.java:99)
	at io.opentelemetry.javaagent.bootstrap.AgentInitializer$1.run(AgentInitializer.java:53)
	at io.opentelemetry.javaagent.bootstrap.AgentInitializer$1.run(AgentInitializer.java:47)
	at io.opentelemetry.javaagent.bootstrap.AgentInitializer.execute(AgentInitializer.java:64)
	at io.opentelemetry.javaagent.bootstrap.AgentInitializer.initialize(AgentInitializer.java:46)
	at io.opentelemetry.javaagent.OpenTelemetryAgent.startAgent(OpenTelemetryAgent.java:57)
	at io.opentelemetry.javaagent.OpenTelemetryAgent.premain(OpenTelemetryAgent.java:45)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:491)
	at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndCallPremain(InstrumentationImpl.java:503)
Caused by: java.lang.ClassNotFoundException: io.opentelemetry.javaagent.shaded.io.opentelemetry.api.metrics.MeterProvider
	at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:445)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:587)
	at io.opentelemetry.javaagent.bootstrap.AgentClassLoader.loadClass(AgentClassLoader.java:161)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
	... 17 more

It seems that MeterProvider is loaded by the Bootstrap Classloader. If the agent classloader cannot load it, will it delegate to the bootstrap?

How should I resolve this problem?

[huange7]

I've noticed something odd; there is no class file for io.opentelemetry.javaagent.shaded.io.opentelemetry.api.metrics.MeterProvider within the javaagent jar. I believe this might be the cause of the issue, but I haven't found an explanation for why this is the case.

[trask]

I've noticed something odd; there is no class file for io.opentelemetry.javaagent.shaded.io.opentelemetry.api.metrics.MeterProvider within the javaagent jar

I see it when I checked the latest release:

$ jar tf opentelemetry-javaagent.jar | grep metrics/MeterProvider.class
io/opentelemetry/javaagent/shaded/io/opentelemetry/api/metrics/MeterProvider.class

[huange7]

Please ignore my question. This is because I have modified the agent code, therefore the compiled agent jar has such problem.