What is wrong with this code?

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Java

public boolean equals(Triangle t) {
        if (this.a.getDistance(this.b) == t.a.getDistance(t.b)
                && this.a.getDistance(this.c) == t.a.getDistance(t.c)
                && this.b.getDistance(this.c) == t.b.getDistance(t.c))
                return true;
               return false;
    }

public boolean isTriangle() {
    if (this.a.getDistance(this.b) < (this.a.getDistance(this.c) + this.b.getDistance(this.c))
            && this.a.getDistance(this.b) > (this.a.getDistance(this.c) - this.b.getDistance(this.c))
            && this.a.getDistance(this.c) < (this.a.getDistance(this.b) + this.b.getDistance(this.c))
            && this.a.getDistance(this.c) > (this.a.getDistance(this.b) - this.b.getDistance(this.c))
            && this.b.getDistance(this.c) < (this.a.getDistance(this.c) + this.a.getDistance(this.b))
            && this.b.getDistance(this.c) > (this.a.getDistance(this.c) - this.a.getDistance(this.b))) {
        return true;
    }
    return false;
}

What I have tried:

I wrote 2classes as Point and Triangle and 2functions above :one of them is equals that i want to check that "do these two triangles equal? " and another function is isTringle that i want to check that can these points be points of triangle like can this points create triangle?


and when i want to run my program i get error like this:

Exception in thread "main" java.lang.NullPointerException
	at javaapplication35.Triangle.equals(Triangle.java:54)
	at javaapplication35.JavaApplication35.main(JavaApplication35.java:34)
C:\Users\User\AppData\Local\NetBeans\Cache\8.1\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 0 seconds)

when i click adresses which errors show me,i go to above equals function.
what is wrong with this function?can anyone help me?
thank you in advance :)

public class JavaApplication35 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Point p1 = new Point(6, 8);
        Point p2 = new Point(3, 4);
        Point p3 = new Point(3, 4);
        /*System.out.println(p1.getDistance(p2));
        System.out.println(p3.getDistance(p2));
        System.out.println(p1.toString());
        System.out.println(p2.toString());
        System.out.println(p3.toString());
        System.out.println(p1.isSame(p2));
        System.out.println(p3.isSame(p2));*/
        Triangle t1 = new Triangle();
        t1.setA(p1);
        t1.setB(p2);
        t1.setC(p3);
        System.out.println((t1.getPerim()));
        Triangle t2 = new Triangle();
        t2.setA(p1);
        t2.setB(p2);
        t2.setC(p3);
        System.out.println(t1.equals(t2));
        System.out.println(t1.isTriangle());
    }
}