向Java项目添加Jar库后Eclipse出现Class File Editor Source not Found提示的问题咨询

Hey there! Let's break this down clearly for you.

Should you worry about this? #

First things first: this prompt doesn't break your project at all. Your Java code will still compile and run just fine, because the JVM only needs the compiled bytecode from the .jar file to execute.

That said, the prompt becomes relevant only if you need to:

• Debug into the third-party library's code to track down bugs
• Understand the internal logic of the library to use it more effectively
• Verify how a specific method works under the hood

If you're just using the library's public APIs and don't need to peek under the hood, you can totally ignore this message and carry on.

How to fix it #

If you do need to view the library's code, here are your options:

1. Attach the official source package #

Most reputable libraries provide a separate source .jar (usually named with a -sources suffix, like gson-2.10.1-sources.jar). Here's how to link it:

• Right-click the third-party .jar in your project's Referenced Libraries → Build Path → Configure Build Path
• Switch to the Libraries tab, expand the .jar entry, and you'll see Source attachment: (none)
• Double-click that line, then browse to select the corresponding source .jar/zip file
• Click OK to save—now when you open any class from the library, you'll see the actual human-readable source code

2. Use Eclipse's built-in decompiler (if no official source exists) #

If you can't find the official source code, Eclipse has a built-in decompiler that can generate readable code from the bytecode:

• When the "Source not Found" banner appears, click the Decompile button on the banner itself
• Alternatively, set it as the default: Go to Window → Preferences → Java → Decompiler, select your preferred decompiler (Eclipse's default JD-Core works great), and click Apply
• Now whenever you open a class without attached source, Eclipse will automatically show you decompiled code (it's not the original source, but it's good enough to understand logic)

3. Just ignore it #

If you don't need to look at the library's internal code, simply close the Class File Editor window. Your project will run perfectly without any changes.

内容的提问来源于stack exchange，提问作者Matt