Merge pull request #31328 from vpavic

* pr/31328:
  Polish "Fix regression in JmsAccessor#setSessionAcknowledgeMode"
  Fix regression in JmsAccessor#setSessionAcknowledgeMode

Closes gh-31328

Author: snicoll

spring-jms/src/main/java/org/springframework/jms/support/JmsAccessor.java

@@ -167,8 +167,6 @@ public void setSessionAcknowledgeModeName(String constantName) {
 	 * @see jakarta.jms.Connection#createSession(boolean, int)
 	 */
 	public void setSessionAcknowledgeMode(int sessionAcknowledgeMode) {
-		Assert.isTrue(sessionConstants.containsValue(sessionAcknowledgeMode),
-				"Only values of acknowledge mode constants allowed");
 		this.sessionAcknowledgeMode = sessionAcknowledgeMode;
 	}
 

spring-jms/src/test/java/org/springframework/jms/support/JmsAccessorTests.java

@@ -98,8 +98,6 @@ void setSessionAcknowledgeModeNameToAllSupportedValues() {
 
 	@Test
 	void setSessionAcknowledgeMode() {
-		assertThatIllegalArgumentException().isThrownBy(() -> accessor.setSessionAcknowledgeMode(999));
-
 		accessor.setSessionAcknowledgeMode(Session.AUTO_ACKNOWLEDGE);
 		assertThat(accessor.getSessionAcknowledgeMode()).isEqualTo(Session.AUTO_ACKNOWLEDGE);
 
@@ -113,6 +111,12 @@ void setSessionAcknowledgeMode() {
 		assertThat(accessor.getSessionAcknowledgeMode()).isEqualTo(Session.SESSION_TRANSACTED);
 	}
 
+	@Test
+	void setCustomSessionAcknowledgeMode() {
+		accessor.setSessionAcknowledgeMode(999);
+		assertThat(accessor.getSessionAcknowledgeMode()).isEqualTo(999);
+	}
+
 	@Test
 	void customAcknowledgeModeIsConsideredClientAcknowledge() throws Exception {
 		Session session = mock();