一个 标识符 是用于由程序员，仅举一个字 变量，方法，类，或标签 。

        // Test1 is a class name identifier 
        public class Test1 {
                public static int add(int a, int b) { // add is identifier for a method
                      return a + b; 
                 }

                public static void main() {
                    int c; // c is identifier for a variable
                    int a = 5;
                    c = add(a, 10);
                    if (c > 10)
                         print("c = " + -c);
                    else
                        print(c);
                    print("Hello World");
                 } 
        }

您在Java程序中的cannot use任何一个Keywords as identifiers

print在您上面的程序中不是Keyword，您可以将print用作identifier

使用print作为标识符后，您的代码如下所示。

//Test1 is a class name identifier 
public class Test1 {
    // add is identifier for a method
    public static int add(int a, int b) {
    return a + b;
}

public static void main(String[] args) {
    int c; // c is identifier for a variable
    int a = 5;
    c = add(a, 10);
    if (c > 10)
        print("c = " + -c); // c is a String
    else
        print(c); // c is a int
    print("Hello World"); // Hello World is a String
}

/**
 * Method Overriding
 */
private static void print(int c) {
    System.out.println("In Integer Print Method "+c);
}

private static void print(String string) {
    System.out.println("In String Print Method "+string);
}

}