JPA transaction error ( Not at the database side, values are persisted )

I'm facing the below error :

Attempt to assign id "com.abc.java" to new instance "com.abc.java" failed; there is already an object in the L1 cache with this id. You must delete this object (in a previous transaction or the current 开发者_StackOverflow社区one) before reusing its id. This error can also occur when a horizontally or vertically mapped classes uses auto-increment application identity and does not use a hierarchy of application identity classes. -