Difference between Arrays and 3 dots (Varargs) in java

• An array is a fixed length collection of objects. e.g. new int[5];
• An ArrayList is a variable length collection of objects. e.g. new ArrayList<Integer>();
• The ... in variadic functions is a part of a method signature denoting an array of parameters. e.g. public void printLines(String... lines)

The three dots can only be used in a method argument, and are called 'varargs'. It means you can pass in an array of parameters without explicitly creating the array.

private void method(String[] args) {} is called like method(new String[]{"first", "second"});

private void method(String... args) {} is called like method("first", "second");