System.out.println("a等于b：" + (a==b));中为什么要有+
public class HelloWorld{
public static void main(String[] args) {
int a=16;
double b=9.5;
String str1="hello";
String str2="imooc";
System.out.println("a等于b：" + (a==b));
System.out.println("a大于b：" + (a>=b));
System.out.println("a小于等于b：" + (a<=b));
System.out.println("str1等于str2：" + (str1 ==str2));
}
}
