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NullPointerException

The run-time error thrown when code calls a method on a null reference.

NullPointerException is thrown when a null reference is dereferenced; since Java 15 its helpful message names the null expression, with local variable names when compiled with -g.

Examples

  • String s = null; s.length(); throws NullPointerException, and the message says what was null.

See also

null exception
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