Bump minimum compiler version to Java 16 (#71989)

.ci/java-versions.properties

@@ -4,5 +4,5 @@
 # build and test Elasticsearch for this branch. Valid Java versions
 # are 'java' or 'openjdk' followed by the major release number.
 
-ES_BUILD_JAVA=openjdk15
+ES_BUILD_JAVA=openjdk16
 ES_RUNTIME_JAVA=openjdk11

buildSrc/src/main/java/org/elasticsearch/gradle/internal/info/GlobalBuildInfoPlugin.java

@@ -248,7 +248,7 @@ public class GlobalBuildInfoPlugin implements Plugin<Project> {
 
     private static void assertMinimumCompilerVersion(JavaVersion minimumCompilerVersion) {
         JavaVersion currentVersion = Jvm.current().getJavaVersion();
-        if (minimumCompilerVersion.compareTo(currentVersion) > 0) {
+        if (System.getProperty("idea.active", "false").equals("true") == false && minimumCompilerVersion.compareTo(currentVersion) > 0) {
             throw new GradleException(
                 "Project requires Java version of " + minimumCompilerVersion + " or newer but Gradle JAVA_HOME is " + currentVersion
             );

buildSrc/src/main/resources/minimumCompilerVersion

@@ -1 +1 @@
-15
+16