Class java.util.Random 
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Class java.util.Random 

Object
   |
   +----java.util.Random
public class Random
extends Object
implements Serializable
An instance of this class is used to generate a stream of pseudorandom numbers. The class uses a 48-bit seed, which is modified using a linear congruential formula. (See Donald Knuth, The Art of Computer Programming, Volume 2, Section 3.2.1.)

If two instances of Random are created with the same seed, and the same sequence of method calls is made for each, they will generate and return identical sequences of numbers.

Many applications will find the random method in class Math simpler to use.

Version:
1.17, 07/01/98
Author:
Frank Yellin
Since:
JDK1.0
See Also:
random()

Constructor Index

o java.util.Random()
Creates a new random number generator.
o java.util.Random(long)
Creates a new random number generator using a single long seed.

Method Index

o next(int)
Generates the next pseudorandom number.
o nextBytes(byte[])
Generates a user specified number of random bytes.
o nextDouble()
Returns the next pseudorandom, uniformly distributed double value between 0.0 and 1.0 from this random number generator's sequence.
o nextFloat()
Returns the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence.
o nextGaussian()
Returns the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.
o nextInt()
Returns the next pseudorandom, uniformly distributed int value from this random number generator's sequence.
o nextLong()
Returns the next pseudorandom, uniformly distributed long value from this random number generator's sequence.
o setSeed(long)
Sets the seed of this random number generator using a single long seed.

Constructors

o Random 
public Random()
Creates a new random number generator. Its seed is initialized to a value based on the current time.

Since:
JDK1.0
See Also:
currentTimeMillis()
o Random 
public Random(long seed)
Creates a new random number generator using a single long seed.

Parameters:
seed - the initial seed.
Since:
JDK1.0
See Also:
setSeed(long)

Methods

o next 
protected synchronized int next(int bits)
Generates the next pseudorandom number. Subclass should override this, as this is used by all other methods.

Parameters:
bits - random bits
Returns:
the next pseudorandom value from this random number generator's sequence.
Since:
JDK1.1
o nextBytes 
public void nextBytes(byte bytes)
Generates a user specified number of random bytes.

Since:
JDK1.1
o nextDouble 
public double nextDouble()
Returns the next pseudorandom, uniformly distributed double value between 0.0 and 1.0 from this random number generator's sequence.

Returns:
the next pseudorandom, uniformly distributed double value between 0.0 and 1.0 from this random number generator's sequence.
Since:
JDK1.0
o nextFloat 
public float nextFloat()
Returns the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence.

Returns:
the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence.
Since:
JDK1.0
o nextGaussian 
public synchronized double nextGaussian()
Returns the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.

Returns:
the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.
Since:
JDK1.0
o nextInt 
public int nextInt()
Returns the next pseudorandom, uniformly distributed int value from this random number generator's sequence.

Returns:
the next pseudorandom, uniformly distributed int value from this random number generator's sequence.
Since:
JDK1.0
o nextLong 
public long nextLong()
Returns the next pseudorandom, uniformly distributed long value from this random number generator's sequence.

Returns:
the next pseudorandom, uniformly distributed long value from this random number generator's sequence.
Since:
JDK1.0
o setSeed 
public synchronized void setSeed(long seed)
Sets the seed of this random number generator using a single long seed.

Parameters:
seed - the initial seed.
Since:
JDK1.0 
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