JavaEngine: avoid setting classloader

If a ClassLoader sticks around it will prevent future versions of
classes from being loaded. There is no evidence that preserving the
ClassLoader is actually necessary for annotation processing at this
time.

Author: hinerm

src/main/java/org/scijava/plugins/scripting/java/JavaEngine.java

@@ -222,12 +222,9 @@ public Class<?> compile(String script) throws ScriptException {
 				for (int i = 0; i < urls.length; i++)
 					urls[i] =
 						new URL("file:" + paths[i] + (paths[i].endsWith(".jar") ? "" : "/"));
-				URLClassLoader classLoader =
-					new URLClassLoader(urls, Thread.currentThread()
-						.getContextClassLoader());
 
-				// needed for annotation processing
-				Thread.currentThread().setContextClassLoader(classLoader);
+				final URLClassLoader classLoader =  new URLClassLoader(urls, Thread.currentThread()
+						.getContextClassLoader());
 
 				// load main class
 				return classLoader.loadClass(mainClass);