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Jonas Bonér

Present.
Entrepreneur.
Hacker.
Public Speaker.
Powder Skier.
Perpetual Learner.
Jazz Fanatic.
Wannabee Musician.

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The Optimized Null Check Pattern

A friend of mine showed me The Optimized Null Check Pattern (TM) yesterday (found in a piece of production code): 
public static boolean isNull(Object obj) {
    boolean isNull;
    try {
        obj.toString();
        isNull = false;
    } catch (NullPointerException e) {
        isNull = true;
    }
    return isNull;
}
Then a colleague pointed out to me that a variation of the pattern (not as clean though) is actually used by Sun. From the java.util.logging.LogRecord class: 
public LogRecord(Level level, String msg) {
    // Make sure level isn't null, by calling random method.

    level.getClass();

    ...
}