TransientThreadsafe.java

import java.util.Map;

import org.jruby.Ruby;
import org.jruby.embed.LocalContextScope;
import org.jruby.embed.LocalVariableBehavior;
import org.jruby.embed.ScriptingContainer;

public class TransientThreadsafe {

    private TransientThreadsafe() {
        ScriptingContainer container = 
            new ScriptingContainer(LocalContextScope.THREADSAFE, LocalVariableBehavior.TRANSIENT);
        Runner runner1 = new Runner(container);
        Runner runner2 = new Runner(container);
        new Thread(runner1, "Runner-1").start();
        new Thread(runner2, "Runner-2").start();
        runner1.getVarMap().put("$tmp", "Atlanta");
        runner2.getVarMap().put("$tmp", "Los Angeles");
    }

    public static void main(String[] args) {
        new TransientThreadsafe();
    }
    
    class Runner implements Runnable {
        ScriptingContainer container;
        Map varMap = null;
        
        Runner(ScriptingContainer container) {
            this.container = container;
        }

        @Override
        public void run() {
            varMap = container.getProvider().getVarMap();
            while (varMap == null || varMap.get("$tmp") == null) {
                try {
                    Thread.currentThread().sleep(1000L);
                } catch (InterruptedException e) {
                    // no-op
                }
            }
            container.runScriptlet("puts \"" + Thread.currentThread().getName() + " ran in #{$tmp}\"");
        }

        Map getVarMap() {
            while(varMap == null) {
                try {
                    Thread.currentThread().sleep(1000L);
                } catch (InterruptedException e) {
                    // no-op
                }
            }
            return varMap;
        }
    }
}

Thread.currentThread().sleep(1000L); should just be written as Thread.sleep(1000L); since sleep() is a static method