jdk源码学习1-001 java.lang.Math

java.lang.Math的结构图：

   

 打开jdk源码里面的src.zip，在java.lang的包下有Math.java，1.8版本有77个方法，与

import java.util.Random;（随机数）

import sun.misc.FloatConsts;（定义的是一些静态变量）

import sun.misc.DoubleConsts;（定义的是一些静态变量）

如：

public class DoubleConsts {

public static final double POSITIVE_INFINITY = Double.POSITIVE_INFINITY;
public static final double NEGATIVE_INFINITY = Double.NEGATIVE_INFINITY;
public static final double NaN = Double.NaN;
public static final double MAX_VALUE = Double.MAX_VALUE;
public static final double MIN_VALUE = Double.MIN_VALUE;
public static final double MIN_NORMAL = 2.2250738585072014E-308D;
public static final int SIGNIFICAND_WIDTH = 53;
public static final int MAX_EXPONENT = 1023;
public static final int MIN_EXPONENT = -1022;
public static final int MIN_SUB_EXPONENT = -1074;
public static final int EXP_BIAS = 1023;
public static final long SIGN_BIT_MASK = Long.MIN_VALUE;
public static final long EXP_BIT_MASK = 9218868437227405312L;
public static final long SIGNIF_BIT_MASK = 4503599627370495L;
}