Hi,

the following script works under MRI 1.9, but not under jruby 1.9 (but
in jruby 1.8):

require 'thread'

class MutexedBoolean
    def initialize(initial_value)
        @value = initial_value
        @mutex = Mutex.new
    end
    def true?
        @mutex.synchronize do
            @value == true
        end
    end
end

threads = []

run = MutexedBoolean.new(true)

Thread.abort_on_exception = true

threads << Thread.new do
    while run.true?
        puts "1"
        sleep 1
    end
end

threads << Thread.new do
    while run.true?
        puts "2"
        sleep 1
    end
end

threads.each { |t| t.join }


Here's the stacktrace I'm getting. Only the first thread runs:

Exception in thread "RubyThread-1: threadtest.rb:1"
java.lang.LinkageError: loader (instance of
org/jruby/util/JRubyClassLoader): attempted  duplicate class definition
for name: "threadtest$block_0$RUBY$true?"
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
        at
org.jruby.util.JRubyClassLoader.defineClass(JRubyClassLoader.java:76)
        at
org.jruby.internal.runtime.methods.InvocationMethodFactory.endClassWithBytes(InvocationMethodFactory.java:1358)
        at
org.jruby.internal.runtime.methods.InvocationMethodFactory.getBlockCallback19(InvocationMethodFactory.java:899)
        at
org.jruby.javasupport.util.RuntimeHelpers.createBlockCallback19(RuntimeHelpers.java:177)
        at
org.jruby.javasupport.util.RuntimeHelpers.createCompiledBlockBody19(RuntimeHelpers.java:292)
        at
org.jruby.javasupport.util.RuntimeHelpers.createCompiledBlockBody19(RuntimeHelpers.java:282)
        at
org.jruby.ast.executable.RuntimeCache.createBlockBody19(RuntimeCache.java:442)
        at
org.jruby.ast.executable.RuntimeCache.getBlockBody19(RuntimeCache.java:85)
        at
org.jruby.ast.executable.AbstractScript.getBlockBody190(AbstractScript.java:106)
        at threadtest.method__2$RUBY$true_p_(threadtest.rb:9)
        at
threadtest$method__2$RUBY$true_p_.call(threadtest$method__2$RUBY$true_p_:65535)
        at
threadtest$method__2$RUBY$true_p_.call(threadtest$method__2$RUBY$true_p_:65535)
        at
org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:262)
        at
org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:105)
        at threadtest.block_2$RUBY$__file__(threadtest.rb:31)
        at
threadtest$block_2$RUBY$__file__.call(threadtest$block_2$RUBY$__file__:65535)
        at org.jruby.runtime.CompiledBlock19.yield(CompiledBlock19.java:154)
        at org.jruby.runtime.CompiledBlock19.call(CompiledBlock19.java:82)
        at org.jruby.runtime.Block.call(Block.java:89)
        at org.jruby.RubyProc.call(RubyProc.java:268)
        at org.jruby.RubyProc.call(RubyProc.java:232)
        at org.jruby.internal.runtime.RubyRunnable.run(RubyRunnable.java:95)
        at java.lang.Thread.run(Thread.java:662)

If I remove the @mutex check in true?, it works in jruby 1.9.

thanks,
- Markus