allow support for both spring boot 2 and 3

Signed-off-by: Tihomir Surdilovic <[email protected]>

README.md

@@ -16,7 +16,8 @@ It contains two modules:
 ## Requirements
 
 - Java 1.8+ for build and runtime of core samples
-- Java 1.17+ for build and runtime of Spring Boot samples
+- Java 1.8+ for build and runtime of SpringBoot samples when using SpringBoot 2
+- Java 1.17+ for build and runtime of Spring Boot samples when using SpringBoot 3
 - Local Temporal Server, easiest to get started would be using [Temporal CLI](https://github.com/temporalio/cli).
 For more options see docs [here](https://docs.temporal.io/kb/all-the-ways-to-run-a-cluster).
 
@@ -133,7 +134,8 @@ See the README.md file in each main sample directory for cut/paste Gradle comman
 
 ### Running SpringBoot Samples
 
-These samples use SpringBoot 3
+These samples use SpringBoot 2 by default. To switch to using SpringBoot 3 look at the [gradle.properties](gradle.properties) file
+and follow simple instructions there.
 
 1. Start SpringBoot from main repo dir:
 

build.gradle

@@ -2,7 +2,7 @@ plugins {
     id 'org.cadixdev.licenser' version '0.6.1'
     id "net.ltgt.errorprone" version "3.1.0"
     id 'com.diffplug.spotless' version '6.22.0' apply false
-    id 'org.springframework.boot' version '3.2.0'
+    id "org.springframework.boot" version "${springBootPluginVersion}"
 }
 
 subprojects {
@@ -15,6 +15,16 @@ subprojects {
         options.compilerArgs << "-Werror"
     }
 
+    java {
+        if(project.property("springBootPluginVersion") == "2.7.13") {
+            sourceCompatibility = JavaVersion.VERSION_11
+            targetCompatibility = JavaVersion.VERSION_11
+        } else {
+            sourceCompatibility = JavaVersion.VERSION_17
+            targetCompatibility = JavaVersion.VERSION_17
+        }
+    }
+
     ext {
         otelVersion = '1.30.1'
         otelVersionAlpha = "${otelVersion}-alpha"

gradle.properties

@@ -0,0 +1,4 @@
+springBootPluginVersion=2.7.13
+
+# use this for spring boot 3 support
+#springBootPluginVersion=3.2.0

springboot/build.gradle

@@ -24,9 +24,4 @@ bootJar {
 
 jar {
     enabled = true
-}
-
-java {
-    sourceCompatibility = JavaVersion.VERSION_17
-    targetCompatibility = JavaVersion.VERSION_17
 }