Identify the error in this Java Strategy pattern code snippet:

Identify the error in this Java Strategy pattern code snippet:

interface Strategy { void execute(); }
class ConcreteStrategy implements Strategy {
  public void execute() { System.out.println("Running"); }
}
class Context {
  private Strategy strategy;
  public Context() { }
  public void setStrategy(Strategy s) { strategy = s; }
  public void doWork() { strategy.execute(); }
}
Context c = new Context();
c.doWork();