public static int abs(int a) ,
public static long abs(long a),
public static float abs(float a),
public static double abs(double a), --------------abs方法求绝对值
public static native double acos(double a) -------------acos求反余弦函数
public static native double asin(double a) -------------asin求反正切函数
public static native double atan(double a) -------------atan求反正切函数
public static native double ceil(double a) -------------ceil返回值最小的大于a的整数
public static native double cos(double a) -------------cos求余弦函数
public static native double exp(double a) -------------exp求e的a次幂
public static native double floor(double a) -------------floor返回最大的小于a的数
public static native double log(double a) -------------log返回lna
public static native double pow(double a，double b)------pow求a的b次幂
public static native double sin(double a) -------------sin求正弦函数
public static native double sqrt(double a) -------------sqrt求a的开平方
public static native double tan(double a) -------------tan求正切函数
public static synchronized double random() -------------返回0~1的随机数
native 关键字