Question: How Do I Protect A Jar File?

How can I reduce the size of a jar file?

Larger JAR files take longer to download.

You can reduce the download time of your RIA by applying the following techniques: Compress your RIA’s JAR file by using the pack200 tool.

Remove unnecessary white space from the Java Network Launch Protocol (JNLP) file and the JavaScript files..

Can jar files be decompiled?

2 Answers. Unless you explicitly packaged your source code in the JAR file, there’s no way to get back the original source. You could try using a decompiler (like this) but that will hardly give you nice, readable code.

How do I reverse engineer a jar file?

2 AnswersUse JD-GUI to examine the jar file.Unpack the jar file. jar -xf yourapp.jar.Modify the .class file with a Java Bytecode Editor. Use Java Bytecode Editor (JBE)Repack the modified classes into new archive file. jar -cvf yourapp_patched.jar *.*

How do you use ProGuard?

Enabling ProGuard in Android StudioGo to the build.gradle file of app.Enable the proguard minifyEnabled true.Enable shrinkResources true to reduce the APK size by shrinking resources.proguardFiles getDefaultProguardFile(‘proguard-android. txt’) to enable the default one.

What is the best java decompiler?

5 Best Java DecompilersJD Project. Java Decompiler Project is developed to decompile Java 5 byte code or later versions. … Cavaj Java Decompiler. It is another great tool for converting bytecode to Java source code. … DJ Java Decompiler. … JBVD. … AndroChef Java Decompiler.

What are ProGuard rules?

Proguard is free Java class file shrinker, optimizer, obfuscator, and preverifier. It detects and removes unused classes, fields, methods, and attributes. It optimizes bytecode and removes unused instructions. It renames the remaining classes, fields, and methods using short meaningless names.

Where is ProGuard rules pro?

proguard-rules. txt (or proguard-android. txt ) are in your SDK folder, but if you want to add something to your ProGuard rules you should do this in proguard-rules.pro . You can manually create the file in the \StudioProjects\your_project\app folder and you can add the custom rules.

What do you do with a jar file?

JAR files are packaged with the ZIP file format, so you can use them for tasks such as lossless data compression, archiving, decompression, and archive unpacking. These tasks are among the most common uses of JAR files, and you can realize many JAR file benefits using only these basic features.

How do I convert a jar file to readable?

Open the application, drag and drop your JAR file into it. 1) Go to your jar file’s folder. 2) change it’s extension to . zip….location on your system.Drag and drop the jar for which you want the sources on the JAD. … Click on File menu and select save jar sources.More items…•

What is Fernflower decompiler?

About Fernflower Fernflower is the first actually working analytical decompiler for Java and probably for a high-level programming language in general.

Can we see code in jar file?

Open JD-GUI and File -> open -> open target jar file. It will show java source code.

What is executable JAR file?

Jar files (Java ARchive files) can contain Java class files that will run when the jar is executed. A jar is an archiving format that not only stores directories and source files, but can be run as an executable as well. … java files, you must compile them into . class files with a Java compiler ( javac ).

How do I run an executable JAR file?

jar, follow these rules:Open a notepad.exe.Write : java -jar Example. jar.Save it with the extension . bat.Copy it to the directory which has the . jar file.Double click it to run your . jar file.

Are JAR files safe?

1.10, the jar: protocol is only allowed if the MIME type of the file is application/java-archive . A site that serves a file with that type is essentially promising that it has vetted the content and that it is in fact safe to download and execute. Any other file type results in an “Unsafe file type” error.

How can we prevent reverse engineering in Java?

How to avoid Android app decompilation to prevent reverse-engineering.1) Put important code on a Server.2) Debugger Detection Techniques.3) Write important parts of code in C/C++4) Write files natively into . … 5) Obfuscate values when storing them on mobile.6) Add multi-factor security.More items…

How do you prevent jar decompilation?

The best solution to prevent reverse-engineering is to obfuscate the class file so that is will be very hard to reverse-engineer….Decompile Java class file.Create HelloWorld. java as shown below. … Compile HelloWorld. java program and execute it to make sure it works properly. … Decompile HelloWorld.

Can Java bytecode be decompiled?

Java byctecode can be decompiled back to java source code. The decompiled source will generally not look the exact same, but will have the same functionality. If you’re concerned that someone might decompile your source, you can use obfuscators (like ProGuard) to help.

Is ProGuard free?

ProGuard is an open source command-line tool that shrinks, optimizes and obfuscates Java code. … ProGuard is free software and is distributed under the GNU General Public License, version 2. ProGuard is distributed as part of the Android SDK and runs when building the application in release mode.