Math.abs（）报告错误：找不到符号

Question

I'm new to java and I'm trying to figure out how the Math functions work. I can't figure out what I'm missing.

Here's the entire program:

    public class Math {

    public static void main(String args[])
      {
        double x = Math.abs(4); 
        System.out.println(x);   
      }
    }

When I try to compile it, jGRASP says, "Math.java:5: error: cannot find symbol double x = Math.abs(4);"

Answer 1

You called your class Math , so the built-in java.lang.Math class can't be resolved. So Java thinks you're attempting to call your own abs method that doesn't exist.

Call your class something else, or refer to Math.abs with a fully qualified class name: java.lang.Math.abs(4) .

Answer 2

You could also try:

public class MyTest {

public static void main(String args[])
  {
    double x = java.lang.Math.abs(4); 
    System.out.println(x);   
  }
}