dumpa.java

package me.minidigger.dumpa;

import java.io.File;
import java.io.FileOutputStream;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.lang.instrument.Instrumentation;
import java.security.ProtectionDomain;
import java.util.Arrays;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class dumper {
    public static void premain(String agentArgs, Instrumentation inst) {
        System.out.println("agent loaded");
        inst.addTransformer(new transformer());
    }
}

class transformer implements ClassFileTransformer {
    public byte[] transform(ClassLoader loader, String className,
                            Class<?> classBeingRedefined, ProtectionDomain protectionDomain,
                            byte[] classfileBuffer) throws IllegalClassFormatException {
        try {
            if (className != null) {
                // Skip all system classes
                if (!className.startsWith("java") &&
                        !className.startsWith("sun") &&
                        !className.startsWith("javax") && !className.contains("jetbrains") && !className.contains("intellij") &&
//                    !className.startsWith("com") &&
                        !className.startsWith("jdk")) {
//                    !className.startsWith("org")) {

                    // normalize file name and create folder
                    String newName = className.replaceAll("[^a-zA-Z0-9-/]", "_") + ".class";
                    String[] segments = newName.split("/");
                    String fileName = segments[segments.length - 1];
                    segments = Arrays.copyOf(segments, segments.length - 1);
                    String folderName = Stream.of(segments).map(s -> s.length() > 248 ? s.substring(248) : s).collect(Collectors.joining("/"));
                    File folder = new File(new File("D:\\IntellijProjects\\deobfuscator\\dump"), folderName);
                    folder.mkdirs();
                    File file = new File(folder, fileName);
                    System.out.println("Dumping: " + file);
                    try {
                        // dumpa!
                        FileOutputStream fos = new FileOutputStream(file);
                        fos.write(classfileBuffer);
                        fos.close();
                    } catch (Exception ex) {
                        System.out.println("Exception while writing: " + file);
                        ex.printStackTrace();
                    }
                }
            }

        } catch (Exception ex) {
            ex.printStackTrace();
        }
        
        return classfileBuffer;
    }
}