Object Equals

Main.java

public class Main {

  public static void main(String[] args) {
    VulnerableClass a = new VulnerableClass(1);
    VulnerableClass b = new VulnerableClass(2);
    a.equals(b);
  }
}

class VulnerableClass {
  int i;

  public VulnerableClass(int i) {
    this.i = i;
  }

  private void vulnerableMethod() {
    
  }
  
  @Override
  public boolean equals(Object obj) {
    // I am vulnerable
    vulnerableMethod();
    return i == ((VulnerableClass) obj).i;
  }
}

class HarmlessClass {
  @Override
  public boolean equals(Object obj) {
    return super.equals(obj);
  }
}