[MNG-4632] Class loading is not thread-safe

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0-alpha-7
• Fix Version/s: 3.0-beta-1
• Component/s: Class Loading
• Assignee: Kristian Rosenvold
• Reporter: Benjamin Bentmann
• Created: 13/Apr/10 07:04
• Updated: 13/Apr/10 12:54
• Resolved: 13/Apr/10 12:35

Description

During his work on parallel build execution, Kristian Rosenvold discovered

Caused by: java.lang.LinkageError: loader (instance of  org/codehaus/plexus/classworlds/realm/ClassRealm): attempted  duplicate class definition for name: "antlr/TokenWithIndex"
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:634)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
	at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClassFromSelf(ClassRealm.java:386)
	at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:42)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
	at antlr.Utils.loadClass(Utils.java:18)
	at antlr.CharScanner.setTokenObjectClass(CharScanner.java:335)
	at org.antlr.tool.Grammar.parseAndBuildAST(Grammar.java:608)
	at org.antlr.Tool.getRootGrammar(Tool.java:612)
	at org.antlr.tool.BuildDependencyGenerator.<init>(BuildDependencyGenerator.java:89)
	at org.antlr.Tool.buildRequired(Tool.java:359)
	at org.antlr.Tool.process(Tool.java:423)
	at org.antlr.mojo.antlr3.Antlr3Mojo.execute(Antlr3Mojo.java:391)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:105)
	... 14 more

He also provided a patch for classworlds that was already applied r8689.