Strictly speaking, the Java compilers are a bit smarter in that the compiler does the concatenation on the string at compile for adjacent constant strings. In other words, the plus signs (concat operators) in the expression you give are not done at runtime. Both versions will store a single string in the constant pool, that will be loaded into the heap when assigned to a variable (or field). Result is that the GC will be called in both instances.

Been awhile since I've looked at the decompiled code, but just glancing at the results, I don't see any significant difference:


class TestMe {
   private final String RETRIEVE_SQL = "select column1, column2 "
                                          + "from table "
                                          + "where AnyCommonWhereCondition ";

   private static final String STATIC_SQL = "select column1, column2 "
                                             + "from table "
                                             + "where AnyCommonWhereCondition ";

   public static void main(String argv[]) {
      TestMe me = new TestMe();
   }

   TestMe() {
      String s;

      s = RETRIEVE_SQL;
      s = STATIC_SQL;
   }
}


.source                  TestMe.java
.class                   TestMe
.super                   java/lang/Object

.field                   private final RETRIEVE_SQL Ljava/lang/String;
                           = "select column1, column2 from table where AnyCommonWhereCondition "
.field                   private static final STATIC_SQL Ljava/lang/String;
                          = "select column1, column2 from table where AnyCommonWhereCondition "

.method                  public static main([Ljava/lang/String;)V
   .limit stack          2
   .limit locals         2
   .line                 11
   new                   TestMe
   dup                   
   invokespecial         TestMe/<init>()V
   astore_1              
   .line                 12
   return                
.end method              

.method                  <init>()V
   .limit stack          2
   .limit locals         2
   .line                 14
   aload_0               
   invokespecial         java/lang/Object/<init>()V
   .line                 2
   aload_0               
   ldc                   "select column1, column2 from table where AnyCommonWhereCondition "
   putfield              TestMe/RETRIEVE_SQL Ljava/lang/String;
   .line                 17
   ldc                   "select column1, column2 from table where AnyCommonWhereCondition "
   astore_1              
   .line                 18
   ldc                   "select column1, column2 from table where AnyCommonWhereCondition "
   astore_1              
   .line                 19
   return                
.end method