Java Varargs: What Do the Three Dots (...) Mean?

Varargs: What's with the Three Dots?

In Java, you may encounter the ellipsis (...) appended to a parameter type, as seen in the following method declaration:

public void myMethod(String... strings) {
    // method body
}

What's It All About?

The three dots denote varargs, which designates that the method can take an arbitrary number of arguments of the specified type (String in this case). Essentially, varargs expand the flexibility of method arguments, allowing you to pass either an array of the specified type or multiple individual objects of that type.

How to Use It

There are several ways to invoke a varargs method:

• With zero arguments, as in myMethod();.
• With multiple individual arguments, as in myMethod("one", "two", "three").
• With a single array of the specified type, as in myMethod(new String[] { "a", "b", "c" }).
• With an empty array, as in myMethod(new String[0]).

Important Considerations

• The varargs argument must be the last parameter in the method signature.
• The method body must treat the varargs argument as an array, even if a single object is passed. This is because varargs always results in an array in the method implementation.

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