r/javahelp • u/Full_School_7230 • 6d ago

How do developers study Java src code ?

Hey everyone,

I’m currently learning Java to build projects and grind Data Structures & Algorithms (DSA), but I am hitting a massive wall with how the code is structured.

Today, I was trying to implement a simple ServerSocket. To understand what was happening, I instinctively Ctrl+Clicked on it. The IDE immediately unzipped the internal source code and dragged me down a never-ending rabbit hole: from ServerSocket, to SocketImpl, all the way into NioSocketImpl and hidden factory classes.

It throws hundreds of lines of complex internal implementation code at me. It is incredibly time-consuming, frustrating, and completely breaks my momentum. I feel like I'm getting sucked into a black hole of code that I didn't even write, and if I keep this up, I am going to get stuck and fail to actually build anything.

I need a serious reality check and some practical advice:

  1. How do developers actually read and reason about Java without constantly opening up the internal source files?

  2. What is the fastest, cleanest way to look up how to use a class/method without getting bogged down by its underlying implementation code?

  3. How do I force myself to treat things like ServerSocket as "black boxes" so I can just focus on building my app and solving DSA patterns?

Any strategies to help me break this habit and speed up my learning would be deeply appreciated. Thank you!

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u/GermanBlackbot 6d ago

To understand what was happening, I instinctively Ctrl+Clicked on it.

That's the beauty: If you want to understand what's happening, this is a way to do it. If you have the corresponding -sources JAR your IDE will usually use this, but in a pinch it can use the .class files themselves and decompile them, though some details might geht lost along the way this way.

But that's if you want to understand what's happening. Usually you don't need to understand what's happening in detail.

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u/Full_School_7230 6d ago edited 6d ago

What are things that I should ask? The must know things. Suppose, I get to know about a class name now read it's methods and it's working or read docs or or src code.

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u/GermanBlackbot 6d ago

You should ask yourself: "What does this class or method do?"
To understand this, you read the javadoc.

You rarely need to ask yourself: "How does this class do this?"
Because unless the javadoc specifically mentions it, it simply doesn't matter to you. Sure, if you're curious you can dive in, but I don't need to understand how an ArrayList or a HashMap does things under the hood. All I need to know is written down in the Javadoc. If an implementation detail is relevant it will be mentioned in the doc.

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u/Full_School_7230 6d ago

Thank you sir.