guava/src/com/google/common/util/concurrent/ThreadFactoryBuilder.java
public ThreadFactoryBuilder setPriority(int priority) {
    // Thread#setPriority() already checks for validity. These error messages
    // are nicer though and will fail-fast.
    checkArgument(
        priority >= Thread.MIN_PRIORITY,
        "Thread priority (%s) must be >= %s",
        priority,
        Thread.MIN_PRIORITY);
    checkArgument(
        priority <= Thread.MAX_PRIORITY,
        "Thread priority (%s) must be <= %s",
        priority,
        Thread.MAX_PRIORITY);
    this.priority = priority;
    return this;
  }
public ThreadFactoryBuilder setPriority(int priority) {
    // Thread#setPriority() already checks for validity. These error messages
    // are nicer though and will fail-fast.
    checkArgument(
        priority >= Thread.MIN_PRIORITY,
        "Thread priority (%s) must be >= %s",
        priority,
        Thread.MIN_PRIORITY);
    checkArgument(
        priority <= Thread.MAX_PRIORITY,
        "Thread priority (%s) must be <= %s",
        priority,
        Thread.MAX_PRIORITY);
    this.priority = priority;
    return this;
  }
Sets the priority for new threads created with this ThreadFactory.

@param priority the priority for new Threads created with this ThreadFactory
@return this for the builder pattern