ClassSignatureComparerHelper does not find super class (NotFoundException - Error reading siganture)

[Timo Deuschle]

Hi there,

I'm using HotswapAgent in a Spring application (SAP hybris) on Tomcat 7.0.

Every time I change something, I get an exception on console that the superclass of modified class is not found (even if it is in the same package, not a library or something). The hotswapping seems to work, I can see changes I made in the code directly.

Technology:

- Java 8u112 with corresponding DCE VM (DCEVM-light-8u112)

- hotswap-agent 1.0

- Hybris 5.7

- Spring 4.1.7.RELEASE

- Tomcat 7.0.59.0

- IntelliJ IDEA with remote debugger

Java Hierarchy:

Two classes, AbstractCMSComponentController and DefaultCMSComponentController, both in the same package. Changes made to DefaultCMSComponentController and recompile triggered in IntelliJ.

Exception:

HOTSWAP AGENT: 13:58:53.550 ERROR (org.hotswap.agent.util.signature.ClassSignatureComparerHelper) - Error reading siganture
org.hotswap.agent.javassist.NotFoundException: my.package.storefront.controllers.cms.AbstractCMSComponentController
        at org.hotswap.agent.javassist.ClassPool.get(ClassPool.java:445)
        at org.hotswap.agent.javassist.CtClassType.getSuperclass(CtClassType.java:669)
        at org.hotswap.agent.util.signature.CtClassSignature.getValue(CtClassSignature.java:69)
        at org.hotswap.agent.util.signature.ClassSignatureComparerHelper.getCtClassSignature(ClassSignatureComparerHelper.java:21)
        at org.hotswap.agent.util.signature.ClassSignatureComparerHelper.isDifferent(ClassSignatureComparerHelper.java:37)
        at org.hotswap.agent.util.signature.ClassSignatureComparerHelper.isPoolClassDifferent(ClassSignatureComparerHelper.java:64)
        at org.hotswap.agent.plugin.spring.signature.ClassSignatureComparer.isPoolClassDifferent(ClassSignatureComparer.java:31)
        at org.hotswap.agent.plugin.spring.SpringChangesAnalyzer.classChangeNeedsReload(SpringChangesAnalyzer.java:43)
        at org.hotswap.agent.plugin.spring.SpringChangesAnalyzer.isReloadNeeded(SpringChangesAnalyzer.java:36)
        at org.hotswap.agent.plugin.spring.SpringPlugin$1.transform(SpringPlugin.java:80)
        at org.hotswap.agent.util.HotswapTransformer.transform(HotswapTransformer.java:177)
        at sun.instrument.TransformerManager.transform(TransformerManager.java:188)
        at sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:428)

Tomcat debug config:

dcevm.hotswap=-XXaltjvm=dcevm -javaagent:${HYBRIS_BIN_DIR}/../tools/hotswap-agent/hotswap-agent.jar=disablePlugin=Hibernate,disablePlugin=Jersey2,disablePlugin=Jetty,disablePlugin=ZK,disablePlugin=Logback,disablePlugin=Seam,disablePlugin=ELResolver,disablePlugin=OsgiEquinox,disablePlugin=WebObjects,disablePlugin=Weld,disablePlugin=JBossModules,disablePlugin=Resteasy,disablePlugin=Gae

tomcat.debugjavaoptions=-Xverify:none ${dcevm.hotswap} -DsourceRoot=${HYBRIS_BIN_DIR} -Xdebug -Xnoagent -Xrunjdwp:transport=dt_socket,server=y,address=8000,suspend=n

No other configuration done, just using hotswap agent defaults. Setup basically copied from here. Any ideas how to get rid of that?

Thanks in advance!

[vladimir dvorak]

Try to upgrade to hotswap-agent-1.1.0-SNAPSHOT

https://github.com/HotswapProjects/HotswapAgent/releases/tag/1.1.0-SNAPSHOT

the snapshot release should be stable with enough.

[Timo Deuschle]

I tried the snapshot, the exception is still there.

These lines from the log look suspicious:

HOTSWAP AGENT: 17:43:54.292 INFO (org.hotswap.agent.plugin.spring.SpringPlugin) - Spring plugin initialized - Spring core version '4.1.7.RELEASE'
HOTSWAP AGENT: 17:43:55.446 INFO (org.hotswap.agent.plugin.spring.SpringPlugin) - Registering basePackage my.package.storefront
[...]

HOTSWAP AGENT: 17:45:56.513 ERROR (org.hotswap.agent.util.signature.ClassSignatureComparerHelper) - Error reading siganture

org.hotswap.agent.javassist.NotFoundException: my.package.storefront.controllers.cms.AbstractCMSComponentController

HOTSWAP AGENT: 17:45:57.738 ERROR (org.hotswap.agent.plugin.spring.scanner.ClassPathBeanDefinitionScannerAgent) - basePackage 'my.package.storefront' not associated with any scannerAgent

Package is registered, but afterwards it's not associated. How could that happen? I don't use a properties file to configure the agent, so no extraClasspath or similar is set.

[vladimir dvorak]

I'm not expert on Hybris at all. May be there is some custom classloading mechanism, since it works for plain tomcat/spring. Could you create some minimalistic example to reproduce this bug?

[Matt Ashley]

Hi all,

I'm evaluating this as a replacement for JRebel. Getting the same error as listed above:

HOTSWAP AGENT: 08:21:29.353 RELOAD (org.hotswap.agent.plugin.jvm.AnonymousClassPatchPlugin) - Class 'com/foo/bar/formpanels/DashboardPanel' has been enhanced with anonymous classes for hotswap.

HOTSWAP AGENT: 08:21:29.397 ERROR (org.hotswap.agent.util.signature.ClassSignatureComparerHelper) - Error reading siganture

org.hotswap.agent.javassist.NotFoundException: com.foo.bar.components.listview.Abstract806ListView

at org.hotswap.agent.javassist.ClassPool.get(ClassPool.java:445)

at org.hotswap.agent.javassist.bytecode.Descriptor.toCtClass(Descriptor.java:577)

at org.hotswap.agent.javassist.bytecode.Descriptor.getReturnType(Descriptor.java:479)

at org.hotswap.agent.javassist.CtBehavior.getReturnType0(CtBehavior.java:294)

at org.hotswap.agent.javassist.CtMethod.getReturnType(CtMethod.java:210)

at org.hotswap.agent.util.signature.CtClassSignature.getMethodString(CtClassSignature.java:117)

at org.hotswap.agent.util.signature.CtClassSignature.getValue(CtClassSignature.java:45)

at org.hotswap.agent.util.signature.ClassSignatureComparerHelper.getCtClassSignature(ClassSignatureComparerHelper.java:21)

at org.hotswap.agent.util.signature.ClassSignatureComparerHelper.isDifferent(ClassSignatureComparerHelper.java:37)

at org.hotswap.agent.util.signature.ClassSignatureComparerHelper.isPoolClassDifferent(ClassSignatureComparerHelper.java:64)

at org.hotswap.agent.plugin.spring.signature.ClassSignatureComparer.isPoolClassDifferent(ClassSignatureComparer.java:31)

at org.hotswap.agent.plugin.spring.SpringChangesAnalyzer.classChangeNeedsReload(SpringChangesAnalyzer.java:43)

at org.hotswap.agent.plugin.spring.SpringChangesAnalyzer.isReloadNeeded(SpringChangesAnalyzer.java:36)

at org.hotswap.agent.plugin.spring.SpringPlugin$1.transform(SpringPlugin.java:80)

at org.hotswap.agent.util.HotswapTransformer.transform(HotswapTransformer.java:177)

at sun.instrument.TransformerManager.transform(TransformerManager.java:188)

at sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:428)

HOTSWAP AGENT: 08:21:29.407 ERROR (org.hotswap.agent.util.signature.ClassSignatureComparerHelper) - Error reading siganture

org.hotswap.agent.javassist.NotFoundException: com.foo.bar.formpanels.DashboardPanel

at org.hotswap.agent.javassist.ClassPool.get(ClassPool.java:445)

at org.hotswap.agent.javassist.bytecode.Descriptor.toCtClass(Descriptor.java:577)

at org.hotswap.agent.javassist.bytecode.Descriptor.getParameterTypes(Descriptor.java:430)

at org.hotswap.agent.javassist.CtBehavior.getParameterTypes(CtBehavior.java:286)

at org.hotswap.agent.util.signature.CtClassSignature.getConstructorString(CtClassSignature.java:103)

at org.hotswap.agent.util.signature.CtClassSignature.getValue(CtClassSignature.java:54)

at org.hotswap.agent.util.signature.ClassSignatureComparerHelper.getCtClassSignature(ClassSignatureComparerHelper.java:21)

at org.hotswap.agent.util.signature.ClassSignatureComparerHelper.isDifferent(ClassSignatureComparerHelper.java:37)

at org.hotswap.agent.util.signature.ClassSignatureComparerHelper.isPoolClassDifferent(ClassSignatureComparerHelper.java:64)

at org.hotswap.agent.plugin.spring.signature.ClassSignatureComparer.isPoolClassDifferent(ClassSignatureComparer.java:31)

at org.hotswap.agent.plugin.spring.SpringChangesAnalyzer.classChangeNeedsReload(SpringChangesAnalyzer.java:43)

at org.hotswap.agent.plugin.spring.SpringChangesAnalyzer.isReloadNeeded(SpringChangesAnalyzer.java:36)

at org.hotswap.agent.plugin.spring.SpringPlugin$1.transform(SpringPlugin.java:80)

at org.hotswap.agent.util.HotswapTransformer.transform(HotswapTransformer.java:177)

at sun.instrument.TransformerManager.transform(TransformerManager.java:188)

at sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:428)

Class changes seem to work, but any change produces a similar error above. Tried both currently release and 1.1 snapshot.

Thanks,

Matt