You might know that Java passes by value, but it helps to understand why. Here's what happens when you pass mutable and immutable object references in Java.

Method references: A primer. My previous Java 101 tutorial introduced lambda expressions, which are used to define anonymous methods that can then be treated as instances of a functional interface.

Java stores object values in heap memory; references to the value are stored in the stack. Another way to create strings is to use the new keyword, as in the following example. String s1 = new String( ...