Question

What is the difference between these 4 method signatures, and why does the 4th not work?

public void main(String args[]) {... } 
public void main(String[] args) {... }
public void main(String... args) {... }
public void main(String[] args[]) {... }

Answer 1

The first three are equivalent.^* The last one is equivalent to String[][] args (i.e. an array of arrays), which doesn’t match what Java requires for main.

However, the idiomatic version is the second one.

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_{* The third one is only valid from Java 5 onwards.}