OOM flavours, side gist for OOM-diag checklist, with thanks from Plumbr: https://plumbr.eu/outofmemoryerror/java-heap-space

OOM.java

/**
 * Run with Heap set to 12MB and 13MB respectively
 * Thanks Plumbr
 */
class OOM {
  static final int SIZE=2*1024*1024;
  public static void main(String[] a) {
    int[] i = new int[SIZE];
   }
}

OOMLeak.java

/**
 * Equals... thanks Plumbr.
 */
class KeylessEntry {
 
   static class Key {
      Integer id;
 
      Key(Integer id) {
         this.id = id;
      }
 
      @Override
      public int hashCode() {
         return id.hashCode();
      }
   }
 
   public static void main(String[] args) {
      Map m = new HashMap();
      while (true)
         for (int i = 0; i < 10000; i++)
            if (!m.containsKey(new Key(i)))
               m.put(new Key(i), "Number:" + i);
   }
}