What is the meaning of the JobExecutor configuration properties in jBPM 3.2?

Issue

We are using jBPM 3.2 and would like to know the meaning of the JobExecutor properties defined in jbpm.cfg.xml:

  <bean name="jbpm.job.executor" class="org.jbpm.job.executor.JobExecutor">
    <field name="jbpmConfiguration"><ref bean="jbpmConfiguration" /></field>
    <field name="name"><string value="JbpmJobExector" /></field>
    <field name="nbrOfThreads"><int value="1" /></field>
    <field name="idleInterval"><int value="5000" /></field>
    <field name="maxIdleInterval"><int value="3600000" /></field> <!-- 1 hour -->
    <field name="historyMaxSize"><int value="20" /></field>
    <field name="maxLockTime"><int value="600000" /></field> <!-- 10 minutes -->
    <field name="lockMonitorInterval"><int value="60000" /></field> <!-- 1 minute -->
    <field name="lockBufferTime"><int value="5000" /></field> <!-- 5 seconds -->
  </bean>