老师您好，为什么这类System.out.println("a等于b：" + (a == b));打印出来的结果会是布尔值呢，在哪里写着boolean了呢
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));
}
}
