Help on line detection

Processing Coding Questions
1

Im working on a maze game, and cant find out how to detect if the ball hits the walls/lines!

int x;
int y;
int s;

void setup(){
  size(500,500);
  background(0);
  noStroke();
  x = 20;
  y = 20;
  s = 10;
  fill(0,0,255);
  ellipse(x,y,s,s);  
  
}

void draw(){ 
  background(0); 
  ellipse(x,y,s,s);
  println(mouseX+" "+mouseY);
  fill(255);
  line(0,45,348,45);
  
  stroke(100);
  line(410,46,410,249);
  stroke(100);
  line(348,45,351,249);
  line(288,45,288,357);
  line(410,297,410,500);
  line(288,358,349,357);
  line(349,357,351,298);
  line(410,412,289,412);
  line(231,412,231,500);
  line(289,456,357,456);
  line(473,0,473,500);
  line(231,357,65,357);
  line(473,497,410,497);
  line(231,300,231,108);
}
void keyPressed(){
  if (key == 'w' || key == 'W') {
    y = y - 5;     
  }
  if (key == 's' || key == 'S') {
    y = y + 5; 
  }
  if (key == 'a' || key == 'A') {
    x = x - 5; 
  }
  if (key == 'd' || key == 'D') {
    x = x + 5; 
  }
  x = constrain(x,0,height);
  y = constrain(y,0,height);
  //https://forum.processing.org/two/discussion/1028/maze
}
2

There are a lot of bouncing ball tutorials for Processing – see for example the examples section. Start with the simplest example first:

In general, the principle to detect if the ball hits the walls is circle-line collision detection, covered with a working example in this guide:

You may also be interested in one of several video tutorials on the bouncing ball problem: