Call to Thread run() instead of start()

Description

In most cases a direct call to a Thread object's run() method is a bug. The programmer intended to begin a new thread of control, but accidentally called run() instead of start(), so the run() method will execute in the caller's thread of control.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

The following excerpt from a Java program mistakenly calls run() instead of start().

Thread thr = new Thread() {
  public void run() {
    ...
  }
};

thr.run();

See Also