Description Alexander Kriegisch 2014-05-21 16:26:52 EDT

Created attachment 243368 [details]
Sample source code

I tried to help somebody on http://stackoverflow.com/questions/23787068/aspect-breaking-bytecode-on-specific-class. I was able to reduce his sample code to something simple. Obviously there are problems with Java 8 when using nested 'forEach' loops with lambda expressions.

Here is my sample application:

package de.scrum_master.app;

import java.util.HashMap;
import java.util.Map;

public class Application {
	public static void main(String[] args) {
		Map<String, Map<Integer, String>> languages = new HashMap<>();

		Map<Integer, String> englishNumbers = new HashMap<>();
		englishNumbers.put(11, "eleven");
		englishNumbers.put(12, "twelve");
		englishNumbers.put(13, "thirteen");
		languages.put("EN", englishNumbers);

		Map<Integer, String> germanNumbers = new HashMap<>();
		germanNumbers.put(11, "elf");
		germanNumbers.put(12, "zwölf");
		germanNumbers.put(13, "dreizehn");
		languages.put("DE", germanNumbers);

		languages.entrySet().stream().forEach((language) -> {
			String languageCode = language.getKey();
			Map<Integer, String> numbers = language.getValue();
			System.out.println("Language code = " + languageCode);
//			numbers.entrySet().stream().forEach((number) -> {
//				int numericValue = number.getKey();
//				String textualValue = number.getValue();
//				System.out.println("  " + numericValue + " -> " + textualValue);
//			});
		});
	}
}


And here is a simple aspect:

package de.scrum_master.aspect;

import de.scrum_master.app.Application;

public aspect MyAspect {
	before() : execution(* Application.*(..)) {
		System.out.println(thisJoinPointStaticPart);
	}
}


This works as expected, the output is:

execution(void de.scrum_master.app.Application.main(String[]))
execution(void de.scrum_master.app.Application.lambda$0(Map.Entry))
Language code = DE
execution(void de.scrum_master.app.Application.lambda$0(Map.Entry))
Language code = EN


But now uncomment the inner 'forEach' loop, i.e. this part:

			numbers.entrySet().stream().forEach((number) -> {
				int numericValue = number.getKey();
				String textualValue = number.getValue();
				System.out.println("  " + numericValue + " -> " + textualValue);
			});


This yields the following exception when starting the driver application:

Exception in thread "main" java.lang.ClassFormatError: Invalid length 65517 in LocalVariableTable in class file de/scrum_master/app/Application
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:367)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:495)


A dirty workaround is to exclude the lambda methods in the pointcut like this:

	before() : execution(* Application.*(..)) && !execution(* *.lambda$*(..)) {
		System.out.println(thisJoinPointStaticPart);
	}


Now it works again and the output is:

execution(void de.scrum_master.app.Application.main(String[]))
Language code = DE
  11 -> elf
  12 -> zwölf
  13 -> dreizehn
Language code = EN
  11 -> eleven
  12 -> twelve
  13 -> thirteen