How does a method signature of only "static" work?

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Static initializer in Java

I have a few years' experience with Java, but I've recently run across something I've never seen before:

public class Project{
...
static{
  initDataTypeMapping();
}
...
}

How does this method signature work? Is this in fact even technically a method? I'm wondering why one wouldn't simply put the the method call to initDataTypeMapping() in the constructor. Just trying to increase my understanding so I don't mess something up. Thanks!

score 6 · Accepted Answer · edited May 23 '17 at 11:53

6

This is known as a static initializer.

The code in the static { } block is run when the class is first loaded by the classloader (which is usually, but not always, when code that refers to the class is first loaded/executed), and is guaranteed to be run in a thread-safe manner.

See this question also.

edited May 23 '17 at 11:53

Community

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answered Jul 05 '12 at 18:02

matt b

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The code is only run once, right? The first time the code is referenced? – FreakinOutMan Jul 05 '12 at 18:09

How does a method signature of only "static" work?

1 Answers1