[#3143] Review and update jopatai's work on the maven/ecj agent jar

* Update copyright headers
* Update code style (tabs, not spaces, spaces around + operator - that's about it)
* Use `x.class.getResourceAsStream`, not `x.getClass().` - minor mostly irrelevant nit.
* Rename and re-locate the jar itself.
* 'ecj' as an alias for this command seems a bit too cavalier' removed it.
* The source is in its own 'root' src dir, it doesn't really fit in the eclipse agent sources - it's more a maven agent.
* Fixed a bug where a filehandle wasn't safe closed. Mostly irrelevant (JVM would quite afterwards anyway).
* Slight rewording of the ecj docs.

3 files changed, 101 insertions, 109 deletions

diff --git a/src/eclipseAgent/lombok/eclipse/agent/MavenEcjBootstrapApp.java b/src/eclipseAgent/lombok/eclipse/agent/MavenEcjBootstrapApp.java
index d08422be..7f9d4d36 100644
--- a/src/eclipseAgent/lombok/eclipse/agent/MavenEcjBootstrapApp.java
+++ b/src/eclipseAgent/lombok/eclipse/agent/MavenEcjBootstrapApp.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009-2022 The Project Lombok Authors.
+ * Copyright (C) 2022 The Project Lombok Authors.
  * 
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -26,7 +26,6 @@ import java.io.FileOutputStream;
 import java.io.FileWriter;
 import java.io.InputStream;
 import java.io.PrintStream;
-import java.util.Arrays;
 import java.util.List;
 
 import com.zwitserloot.cmdreader.CmdReader;
@@ -45,18 +44,14 @@ public class MavenEcjBootstrapApp extends LombokApp {
 	
 	@Override public String getAppDescription() {
 		return "Creates .mvn/jvm.config and .mvn/lombok-bootstrap.jar for\n" +
-				"use with the ECJ compiler.";
-	}
-	
-	@Override public List<String> getAppAliases() {
-		return Arrays.asList("ecj");
+			"use with the ECJ compiler.";
 	}
 	
 	private static class CmdArgs {
 		@Shorthand("w")
 		@Description("Overwrite existing files. Defaults to false.")
 		boolean overwrite = false;
-
+		
 		@Shorthand("o")
 		@Description("The root of a Maven project. Defaults to the current working directory.")
 		String output;
@@ -103,7 +98,7 @@ public class MavenEcjBootstrapApp extends LombokApp {
 			err = e;
 		}
 		if (result != 0) {
-			System.err.println("Could not create "+mvn.getPath());
+			System.err.println("Could not create " + mvn.getPath());
 			if (err != null) err.printStackTrace(System.err);
 		}
 		return result;
@@ -136,15 +131,21 @@ public class MavenEcjBootstrapApp extends LombokApp {
 			return 1;
 		}
 		try {
-			InputStream input = this.getClass().getResourceAsStream("/lombok/eclipse/agent/lombok-bootstrap.jar");
+			InputStream input = MavenEcjBootstrapApp.class.getResourceAsStream("/lombok/launch/mavenEcjBootstrapAgent.jar");
 			FileOutputStream output = new FileOutputStream(jar);
-			byte[] buffer = new byte[4096];
-			int length;
-			while ((length = input.read(buffer)) > 0) output.write(buffer, 0, length);
-			output.flush();
-			output.close();
-			System.out.println("Successfully created: " + canonical(jar));
-			return 0;
+			try {
+				byte[] buffer = new byte[4096];
+				int length;
+				while ((length = input.read(buffer)) > 0) output.write(buffer, 0, length);
+				output.flush();
+				output.close();
+				System.out.println("Successfully created: " + canonical(jar));
+				return 0;
+			} finally {
+				try {
+					output.close();
+				} catch (Exception ignore) {}
+			}
 		} catch (Exception e) {
 			System.err.println("Could not create: " + canonical(jar));
 			e.printStackTrace(System.err);
diff --git a/src/eclipseAgent/lombok/launch/AgentBootstrap.java b/src/eclipseAgent/lombok/launch/AgentBootstrap.java
deleted file mode 100644
index bbd9aa4d..00000000
--- a/src/eclipseAgent/lombok/launch/AgentBootstrap.java
+++ /dev/null
@@ -1,92 +0,0 @@
-/*
- * Copyright (C) 2009-2022 The Project Lombok Authors.
- * 
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- * 
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- * 
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-package lombok.launch;
-
-import java.lang.instrument.ClassFileTransformer;
-import java.lang.instrument.IllegalClassFormatException;
-import java.lang.instrument.Instrumentation;
-import java.net.URL;
-import java.net.URLClassLoader;
-import java.security.ProtectionDomain;
-import java.util.jar.JarFile;
-
-/**
- * This Java agent does not transform bytecode, but acts as a watcher that can figure out when it is appropriate to load
- * Lombok itself within a Maven execution. It relies on several facts:
- * <ul>
- * <li>maven-compiler-plugin contains an AbstractCompilerMojo class that compiler instances extend.
- * <li>Maven loaders are ClassRealms, which extend URLClassLoader.
- * <li>Each plugin dependency in the pom.xml is represented as a file URL on the ClassRealm that points to the artifact.
- * <li>URLs to Maven artifacts contain the group and artifact ids ([...]/groupid/artifactid/ver/artifactid-ver.jar).
- * <li>The Lombok Java agent class is lombok.launch.Agent.
- * </ul>
- * Given all of the above, the transformer simply waits for AbstractCompilerMojo to be loaded, then uses the loader to
- * find the path to the Lombok jar file, and finally loads the Lombok agent using reflection.
- */
-public final class AgentBootstrap
-{
-    private static final String MAVEN_COMPILER_TRIGGER_CLASS = "org/apache/maven/plugin/compiler/AbstractCompilerMojo";
-    private static final String LOMBOK_URL_IDENTIFIER = "/org/projectlombok/lombok/";
-    private static final String LOMBOK_AGENT_CLASS = "lombok.launch.Agent";
-    private static final byte[] NOT_TRANSFORMED = null;
-
-    private AgentBootstrap()
-    {}
-
-    /**
-     * Invoked when agent is added via -javaagent argument.
-     *
-     * @param agentArgs
-     *            arguments
-     * @param instrumentation
-     *            service provider
-     */
-    public static void premain(final String agentArgs, final Instrumentation instrumentation)
-    {
-        instrumentation.addTransformer(new ClassFileTransformer() {
-            @Override
-            public byte[] transform(final ClassLoader loader, final String className, final Class<?> cbr, final ProtectionDomain pd,
-                    final byte[] cfb)
-                throws IllegalClassFormatException
-            {
-                if (MAVEN_COMPILER_TRIGGER_CLASS.equals(className)) {
-                    for (final URL url : ((URLClassLoader)loader).getURLs()) {
-                        if (url.getPath().contains(LOMBOK_URL_IDENTIFIER)) {
-                            try {
-                                instrumentation.appendToSystemClassLoaderSearch(new JarFile(url.getPath()));
-                                AgentBootstrap.class.getClassLoader().loadClass(LOMBOK_AGENT_CLASS)
-                                        .getDeclaredMethod("premain", String.class, Instrumentation.class)
-                                        .invoke(null, agentArgs, instrumentation);
-                                instrumentation.removeTransformer(this);
-                                break;
-                            } catch (final Exception e) {
-                                //There are no appropriate loggers available at this point in time.
-                                e.printStackTrace(System.err);
-                            }
-                        }
-                    }
-                }
-                return NOT_TRANSFORMED;
-            }
-        });
-    }
-}
diff --git a/src/mavenEcjBootstrapAgent/lombok/launch/MavenEcjBootstrapAgent.java b/src/mavenEcjBootstrapAgent/lombok/launch/MavenEcjBootstrapAgent.java
new file mode 100644
index 00000000..b36e591f
--- /dev/null
+++ b/src/mavenEcjBootstrapAgent/lombok/launch/MavenEcjBootstrapAgent.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2022 The Project Lombok Authors.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package lombok.launch;
+
+import java.lang.instrument.ClassFileTransformer;
+import java.lang.instrument.IllegalClassFormatException;
+import java.lang.instrument.Instrumentation;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.security.ProtectionDomain;
+import java.util.jar.JarFile;
+
+/**
+ * This Java agent does not transform bytecode, but acts as a watcher that can
+ * figure out when it is appropriate to load Lombok itself within a Maven
+ * execution.
+ * 
+ * It relies on several facts:
+ * <ul>
+ * <li>maven-compiler-plugin contains an {@code AbstractCompilerMojo} class that
+ * compiler instances extend.
+ * <li>Maven loaders are {@code ClassRealms}, which extend {@code URLClassLoader}.
+ * <li>Each plugin dependency in the <em>pom.xml </em>is represented as a file URL on the
+ * ClassRealm that points to the artifact.
+ * <li>URLs to Maven artifacts contain the group and artifact ids
+ * ({@code [...]/groupid/artifactid/ver/artifactid-ver.jar}).
+ * <li>The Lombok Java agent class is {@code lombok.launch.Agent}.
+ * </ul>
+ * Given all of the above, the transformer simply waits for {@code AbstractCompilerMojo}
+ * to be loaded, then uses the loader to find the path to the Lombok jar file,
+ * and finally loads the Lombok agent using reflection.
+ */
+public final class MavenEcjBootstrapAgent {
+	private static final String MAVEN_COMPILER_TRIGGER_CLASS = "org/apache/maven/plugin/compiler/AbstractCompilerMojo";
+	private static final String LOMBOK_URL_IDENTIFIER = "/org/projectlombok/lombok/";
+	private static final String LOMBOK_AGENT_CLASS = "lombok.launch.Agent";
+	private static final byte[] NOT_TRANSFORMED = null;
+	
+	private MavenEcjBootstrapAgent() {}
+	
+	public static void premain(final String agentArgs, final Instrumentation instrumentation) {
+		instrumentation.addTransformer(new ClassFileTransformer() {
+			@Override public byte[] transform(final ClassLoader loader, final String className, final Class<?> cbr, final ProtectionDomain pd, final byte[] cfb) throws IllegalClassFormatException {
+				if (MAVEN_COMPILER_TRIGGER_CLASS.equals(className)) {
+					for (final URL url : ((URLClassLoader) loader).getURLs()) {
+						if (url.getPath().contains(LOMBOK_URL_IDENTIFIER)) {
+							try {
+								instrumentation.appendToSystemClassLoaderSearch(new JarFile(url.getPath()));
+								MavenEcjBootstrapAgent.class.getClassLoader().loadClass(LOMBOK_AGENT_CLASS).getDeclaredMethod("premain", String.class, Instrumentation.class).invoke(null, agentArgs, instrumentation);
+								instrumentation.removeTransformer(this);
+								break;
+							} catch (Exception e) {
+								// There are no appropriate loggers available at
+								// this point in time.
+								e.printStackTrace(System.err);
+							}
+						}
+					}
+				}
+				return NOT_TRANSFORMED;
+			}
+		});
+	}
+}