demikhov@theLab ~/Desktop/experiment $ vim t.java
demikhov@theLab ~/Desktop/experiment $ javac t.java
t.java:3: incompatible types
found   : int
required: boolean
        boolean flag = 1;
                       ^
1 error
demikhov@theLab ~/Desktop/experiment $ cat t.java
class t {
    public static void main(String[] args) {
        boolean flag = 1;
        System.out.println("Done!");
    }
}