Method initCause

lib/java/lang/Throwable.java:346–355

Initializes the cause of this Throwable. The cause can only be initialized once. @param throwable the cause of this Throwable. @return this Throwable instance. @throws IllegalArgumentException if Throwable is this object. @throws IllegalStateEx

(Throwable throwable)

     *             if the cause has already been initialized.
     */
    public synchronized Throwable initCause(Throwable throwable) {
        if (cause == this) {
            if (throwable != this) {
                cause = throwable;
                return this;
            }
            throw new IllegalArgumentException("Cause cannot be the receiver");
        }
        throw new IllegalStateException("Cause already initialized");
    }

    /**
     * Returns the cause of this {@code Throwable}, or {@code null} if there is