Add || string concatenation operator (#418)

Signed-off-by: Lukas Jungmann <[email protected]>
Co-authored-by: Lukas Jungmann <[email protected]>

spec/src/main/asciidoc/appendixes.adoc

@@ -1,5 +1,5 @@
 //
-// Copyright (c) 2017, 2022 Contributors to the Eclipse Foundation
+// Copyright (c) 2017, 2023 Contributors to the Eclipse Foundation
 //
 
 [appendix]
@@ -101,3 +101,7 @@ Clarified definition of the _Basic_ type
 Clarified the order of parameters in the _LOCATE_ function
 
 Clarified `SqlResultSetMapping` with multiple ``EntityResult``s and conflicting aliases
+
+=== Jakarta Persistence 3.2
+
+Added `||` string concatenation operator

spec/src/main/asciidoc/ch04-query-language.adoc

@@ -1,5 +1,5 @@
 //
-// Copyright (c) 2017, 2022 Contributors to the Eclipse Foundation
+// Copyright (c) 2017, 2023 Contributors to the Eclipse Foundation
 //
 
 == Query Language [[a4665]]
@@ -1209,6 +1209,7 @@ The operators are listed below in order of decreasing precedence.
 ** +, - unary
 ** *, / multiplication and division
 ** +, - addition and subtraction
+* String concatenation (_||_)
 * Comparison operators: _=_, _>_, _>=_, _<_
 , _<=_, _<>_ (not equal), _[NOT]_ _BETWEEN_, _[NOT]_ _LIKE_, _[NOT]_
 _IN_, _IS_ _[NOT]_ _NULL_, _IS_ _[NOT]_ _EMPTY_, _[NOT]_ _MEMBER_
@@ -1655,6 +1656,11 @@ Arithmetic operations use numeric promotion.
 
 Arithmetic functions are described in <<a5284>>.
 
+===== String concatenation operator
+
+The binary concatenation operator is ||.
+Its operands must be string expressions.
+
 ===== Built-in String, Arithmetic, and Datetime Functional Expressions
 
 The Jakarta Persistence query language includes
@@ -2741,8 +2747,8 @@ non-like type values are disallowed except for this numeric case.
 
 [NOTE]
 ====
-Note that the arithmetic operators and
-comparison operators are permitted to be applied to state fields and
+Note that the arithmetic operators, the string concatenation operator,
+and comparison operators are permitted to be applied to state fields and
 input parameters of the wrapped Java class equivalents to the primitive
 numeric Java types.
 ====
@@ -3084,6 +3090,7 @@ string_expression ::=
     aggregate_expression |
     case_expression |
     function_invocation |
+    string_expression || string_expression
     (subquery)
 datetime_expression ::=
     state_valued_path_expression |