Class ThreadLocalRandom

  • All Implemented Interfaces:
    Serializable

    public final class ThreadLocalRandom
    extends Random
    A random number generator isolated to the current thread. Like the global Random generator used by the Math class, a ThreadLocalRandom is initialized with an internally generated seed that may not otherwise be modified. When applicable, use of ThreadLocalRandom rather than shared Random objects in concurrent programs will typically encounter much less overhead and contention. Use of ThreadLocalRandom is particularly appropriate when multiple tasks use random numbers in parallel in thread pools.

    Usages of this class should typically be of the form: ThreadLocalRandom.current().nextX(...) (where X is Int, Long, etc). When all usages are of this form, it is never possible to accidently share a ThreadLocalRandom across multiple threads.

    This class also provides additional commonly used bounded random generation methods.

    Since:
    1.7
    See Also:
    Serialized Form
    • Constructor Detail

      • ThreadLocalRandom

        public ThreadLocalRandom()
    • Method Detail

      • current

        public static ThreadLocalRandom current()
        Returns the current thread's ThreadLocalRandom.
        Returns:
        the current thread's ThreadLocalRandom
      • setSeed

        public void setSeed​(long seed)
        Throws UnsupportedOperationException. Setting seeds in this generator is not supported.
        Overrides:
        setSeed in class Random
        Throws:
        UnsupportedOperationException - always
      • next

        protected int next​(int bits)
        Overrides:
        next in class Random