question: @ Override public Object remove ( Object key ) { Entry tab [ ] = table ; if ( key != null ) { int hash = System . identityHashCode ( key ) ; int index = ( hash & 0x7FFFFFFF ) % tab . length ; for ( Entry e = tab [ index ] , prev = null ; e != null ; prev = e , e = e . next ) { if ( ( e . hash == hash ) && key == e . key ) { modCount ++ ; if ( prev != null ) prev . next = e . next ; else tab [ index ] = e . next ; count -- ; Object oldValue = e . value ; e . value = null ; return oldValue ; } } } else { for ( Entry e = tab [ 0 ] , prev = null ; e != null ; prev = e , e = e . next ) { if ( e . key == null ) { modCount ++ ; if ( prev != null ) prev . next = e . next ; else tab [ 0 ] = e . next ; count -- ; Object oldValue = e . value ; e . value = null ; return oldValue ; } } } return null ; }
target:  Removes the mapping for this key from this map if present.