JavaEngine: always to try clean up the mess

Even if the error occurred during the builder initialization, rather
than the build step, let's make sure to try calling cleanup() afterward.

This change makes the code simpler, too, since we no longer need nested
try/catch/finally blocks.

This is an attempted bug-fix for Fiji BugZilla issue #906:
    http://fiji.sc/bugzilla/show_bug.cgi?id=906

This patch looks best with "git show -b" to ignore whitespace changes.

Author: ctrueden

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

@@ -205,31 +205,26 @@ public Class<?> compile(String script) throws ScriptException {
 			final MavenProject project = builder.project;
 			String mainClass = builder.mainClass;
 
-			try {
-				project.build(true);
+			project.build(true);
+			if (mainClass == null) {
+				mainClass = project.getMainClass();
 				if (mainClass == null) {
-					mainClass = project.getMainClass();
-					if (mainClass == null) {
-						throw new ScriptException("No main class found for file " + file);
-					}
+					throw new ScriptException("No main class found for file " + file);
 				}
+			}
 
-				// make class loader
-				String[] paths = project.getClassPath(false).split(File.pathSeparator);
-				URL[] urls = new URL[paths.length];
-				for (int i = 0; i < urls.length; i++)
-					urls[i] =
-						new URL("file:" + paths[i] + (paths[i].endsWith(".jar") ? "" : "/"));
+			// make class loader
+			String[] paths = project.getClassPath(false).split(File.pathSeparator);
+			URL[] urls = new URL[paths.length];
+			for (int i = 0; i < urls.length; i++)
+				urls[i] =
+					new URL("file:" + paths[i] + (paths[i].endsWith(".jar") ? "" : "/"));
 
-				final URLClassLoader classLoader =  new URLClassLoader(urls, Thread.currentThread()
-						.getContextClassLoader());
+			final URLClassLoader classLoader =  new URLClassLoader(urls, Thread.currentThread()
+					.getContextClassLoader());
 
-				// load main class
-				return classLoader.loadClass(mainClass);
-			}
-			finally {
-				builder.cleanup();
-			}
+			// load main class
+			return classLoader.loadClass(mainClass);
 		}
 		catch (Exception e) {
 			if (writer != null) {
@@ -242,6 +237,9 @@ public Class<?> compile(String script) throws ScriptException {
 				throw new ScriptException(e);
 			}
 		}
+		finally {
+			builder.cleanup();
+		}
 		return null;
 	}
 
@@ -295,16 +293,14 @@ public void compile(final File file, final Writer errorWriter) {
 		final Builder builder = new Builder();
 		try {
 			builder.initialize(file, writer);
-			try {
-				builder.project.build();
-			}
-			finally {
-				builder.cleanup();
-			}
+			builder.project.build();
 		}
 		catch (Throwable t) {
 			printOrThrow(t, errorWriter);
 		}
+		finally {
+			builder.cleanup();
+		}
 	}
 
 	/**
@@ -321,20 +317,18 @@ public void makeJar(final File file, final boolean includeSources,
 		final Builder builder = new Builder();
 		try {
 			builder.initialize(file, errorWriter);
-			try {
-				builder.project.build(true, true, includeSources);
-				final File target = builder.project.getTarget();
-				if (output != null && !target.equals(output)) {
-					BuildEnvironment.copyFile(target, output);
-				}
-			}
-			finally {
-				builder.cleanup();
+			builder.project.build(true, true, includeSources);
+			final File target = builder.project.getTarget();
+			if (output != null && !target.equals(output)) {
+				BuildEnvironment.copyFile(target, output);
 			}
 		}
 		catch (Throwable t) {
 			printOrThrow(t, errorWriter);
 		}
+		finally {
+			builder.cleanup();
+		}
 	}
 
 	/**