Rotates a point around another point

EntryPoint.java

public class EntryPoint {
	public static class Point{
		public final double x;
		public final double y;
		
		public Point(double x,double y){
			this.x = x;
			this.y = y;
		}
		
		public String toString(){
			return "("+this.x+","+this.y+")";
		}
	}
	
	public static void main(String... args) {
		Point curPos = new Point(-10,-10);
		Point rotPos = new Point(0,0);
		
		System.out.println(getRotatedPoint(curPos,rotPos,0).toString());
	}
	
	public static Point getRotatedPoint(Point curPos,Point rotPos,double r){
		//get the current angle from the rotation point to the current point
		double currentRot=getCurRot(curPos,rotPos);
		
		//get the current radius of the circle drawn around the rotPos that intersects the curpos
		double magnitude=getMagnitude(curPos,rotPos);
		
		//MATH STUFFS
		double x = Math.cos(r+currentRot)*magnitude + rotPos.x;
		double y = Math.sin(r+currentRot)*magnitude + rotPos.y;
		
		return new Point(x,y);
	}

	/**
	 * Gets the current angle from the rotational point to the current point
	 * @param curPos The current position
	 * @param rotPos The position of the point that you want to rotate around
	 * @return
	 */
	public static double getCurRot(Point curPos,Point rotPos){
		double diff_y = (curPos.y-rotPos.y);
		double diff_x = (curPos.x-rotPos.x);
		
		double diff = diff_y/diff_x;
		
		if(diff==Double.NaN){
			return 0;
		}
		else{
			double toReturn = Math.atan(diff);
			
			if(diff_y<0 && diff_x<0){
				System.out.println(diff);
				//if both are negative, add pi/2
				toReturn += Math.PI;
				System.out.println("trigger 1");
			}
			else if(diff_x<0 && !(diff_y<0)){
				//if x is less than 0 and y isn't
				toReturn = -toReturn;
				toReturn+=Math.PI/2;
				
				System.out.println("trigger 2");
			}
			
			return toReturn;
		}
	}

	public static double getMagnitude(Point a, Point b){
		double x_dist = Math.abs(a.x-b.x);
		double y_dist = Math.abs(a.y-b.y);
		
		return Math.sqrt(Math.pow(x_dist, 2)+Math.pow(y_dist,2));
	}
}