We’ve all been there. You inherit a legacy project with no source code, a critical dependency throws an unexplainable error, or a vendor goes out of business taking their documentation with you.
Have a war story about decompiling a nasty legacy system? Share it in the comments below.
All you have is a .jar file (or a lone .class file). Is the code lost forever?
public class UserService private String apiKey = "secret"; public String greetUser(String name) name.isBlank()) return "Hello, Guest!"; return "Hello, " + name.trim() + "!";
public class UserService private String apiKey = "secret"; public String greetUser(String name) if (name == null
#!/bin/bash # decompile.sh JAR_FILE=$1 OUTPUT_DIR="./decompiled_src" unzip $JAR_FILE -d ./temp_classes Decompile all .class files find ./temp_classes -name "*.class" -type f | while read class; do java -jar cfr.jar "$class" --outputdir "$OUTPUT_DIR" done Clean up rm -rf ./temp_classes
