Understanding Memory Addresses of Variables in Java

What happens to memory addresses of objects and variables in Java, and how can I convert these addresses to binary?

System.out.println(objName);

In Java, when you create an object using the `new` keyword, the Java Virtual Machine (JVM) allocates memory for that object and returns a reference (or address) to that memory location. When you print an object directly using `System.out.println()`, it calls the object's `toString()` method, which by default returns a string representation that includes the class name followed by the object's hash code in hexadecimal format.

// Example of overriding toString()
@Override
public String toString() {
    return "MyClass [id=" + id + ", name=" + name + "]";
}

// Converting hex to binary
String hexString = Integer.toHexString(obj.hashCode());
int decimal = Integer.parseInt(hexString, 16);
String binaryString = Integer.toBinaryString(decimal);
System.out.println("Binary: " + binaryString);

Causes

• The output string from `System.out.println(objName)` is not the actual memory address but rather a representation derived from the object's hash code.
• Java abstracts memory management, making it unavailable to directly access memory addresses like in languages such as C or C++.

Solutions

• To get a more meaningful representation of the object's address, you can override the `toString()` method in your class to provide custom output.
• For converting the hexadecimal string representation to binary, first parse the hex string to an integer and then convert it to binary.

Mistake: Assuming you can access the raw memory address of a variable directly.

Solution: Understand that Java uses references and provides abstractions for memory management.

Mistake: Using the output of `System.out.println(objName)` as a reliable identifier for memory address.

Solution: Learn to override the `toString()` method or use debugging tools for insights.