Instance Pooling
  • Simple implementation of EJB container:
    • When an entity bean is created, create the corresponding instance
    • When the entity bean is removed, delete (allow to be garbage collected) the instance
  • Problem:
    • Entity beans typically have a long lifetime
    • Over time, more and more instances accumulate in memory
    • Most instances are not actively being used
  • Better implementation
    • Create a fixed size pool of instances
    • When a request arrives:
      • Choose an unused instance and associate it with the bean's PK
      • Use ejbLoad() to sync the bean with the DB
      • Execute the method
      • Return the bean to the pool

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