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    <p>As others have mentioned elsewhere, you can do this by attaching an agent to the JVM, as that is the only place the JVM will report on what classes are loaded.</p> <p>This class shows how that is done:</p> <pre><code>import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.lang.instrument.Instrumentation; import java.lang.reflect.Method; import java.util.HashSet; import java.util.Set; public class ClassReporter implements Runnable { /** Output file */ File output; /** The JVM instrumentation */ Instrumentation instrument; /** Already reported classes */ Set&lt;Class&lt;?&gt;&gt; known = new HashSet&lt;Class&lt;?&gt;&gt;(); /** Is reporter still running? */ volatile boolean running = true; @Override public void run() { System.out.println("Class Reporter agent running"); while( running ) { if (!report()) return; try { Thread.sleep(5000); } catch (InterruptedException ie) { ie.printStackTrace(); return; } } } /** * Update the report of loaded classes * * @return true if report was written OK */ public synchronized boolean report() { Set&lt;Class&lt;?&gt;&gt; report = new HashSet&lt;Class&lt;?&gt;&gt;(); Class&lt;?&gt;[] classes = instrument.getAllLoadedClasses(); for(Class&lt;?&gt; c:classes) { if (known.add(c)) report.add(c); } if (report.isEmpty()) return true; boolean ret = true; FileWriter fw = null; try { fw = new FileWriter(output, true); for(Class&lt;?&gt; c:classes) { fw.write(c.getName()); fw.write('\n'); for(Method m:c.getDeclaredMethods()) { fw.write(m.toGenericString()); fw.write('\n'); } fw.write('\n'); fw.write('\n'); fw.flush(); } } catch (IOException ioe) { ioe.printStackTrace(); ret = false; } finally { if (fw != null) { try { fw.close(); } catch (IOException ioe) { ioe.printStackTrace(); ret = false; } } } return ret; } /** * Initialize the reporter * * @param agentArgs * the output file name * @param inst * the instrumentation */ public static void premain(String agentArgs, Instrumentation inst) { final ClassReporter cr = new ClassReporter(); cr.instrument = inst; File out = new File(agentArgs); out.delete(); try { out.createNewFile(); } catch (IOException ioe) { System.out.println("Class Reporter could not create file " + out.getAbsolutePath()); return; } cr.output = out; Thread thread = new Thread(cr); thread.setDaemon(true); thread.start(); Thread shutdown = new Thread() { public void run() { System.out.println("Class Reporter writing final report"); cr.running = false; cr.report(); System.out.println("Class Reporter done"); } }; Runtime.getRuntime().addShutdownHook(shutdown); } } </code></pre> <p>To turn the class into an agent, you need to package it specially in a JAR file with an appropriate Manifest. The Manifest is:</p> <pre><code>Premain-Class: ClassReporter </code></pre> <p>You then create the agent jar with this command:</p> <pre><code>jar cvfm cr.jar Manifest.mf ClassReporter*.class </code></pre> <p>and then to actually use it, you run the application specifying the agent on the command-line like this:</p> <pre><code>java -javaagent:cr.jar=cr.txt ActualProgramMainClass </code></pre> <p>The "cr.txt" is the output file generated. You will see output on System.out saying the reporter is running. The output file shows all the information you mention in your question.</p>
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