SOLR-16299: Remove symlinks for ref-guide examples (#946)

The example classes now live in the ref-guide module

gradle/validation/spotless.gradle

@@ -57,6 +57,10 @@ configure(project(":solr").subprojects) { prj ->
             // Exclude Hadoop copied files to make upgrades easier
             targetExclude "src/**/org/apache/hadoop/**"
             break
+          case ":solr:solr-ref-guide":
+            // Apply to all example Java sources in the ref-guide
+            target "modules/**/examples/*.java"
+            break
         }
       }
     }

solr/CHANGES.txt

@@ -146,6 +146,8 @@ Build
 
 * SOLR-16264: Set versions for all Antora build tools (Houston Putman)
 
+* SOLR-16299: Ref-guide examples are no longer symlinked from SolrJ, they live in the ref-guide module (Houston Putman)
+
 ==================  9.0.0 ==================
 
 New Features

solr/solr-ref-guide/build.gradle

@@ -17,8 +17,14 @@
 
 import org.apache.tools.ant.util.TeeOutputStream
 
+apply plugin: 'java'
+
 description = 'Solr Reference Guide'
 
+/*
+ Antora Logic - Building the ref-guide
+ */
+
 def officialSiteIncludePrerelease = propertyOrEnvOrDefault("refguide.official.includePrereleaseVersions", "SOLR_REF_GUIDE_OFFICIAL_INCLUDE_PRERELEASE", "false").toBoolean()
 
 def buildLocalUI = propertyOrEnvOrDefault("refguide.buildLocalUI", "SOLR_REF_GUIDE_BUILD_LOCAL_UI", "false").toBoolean()
@@ -503,3 +509,37 @@ task buildOfficialSite(type: NpxTask) {
         project.logger.lifecycle("\t${project.ext.siteDir}")
     }
 }
+
+/*
+ Compiling, Testing and Validation for the java examples in the Solr Ref Guide
+ */
+
+sourceSets {
+    test {
+        java {
+            srcDirs = ['modules/configuration-guide/examples', 'modules/deployment-guide/examples', 'modules/getting-started/examples', 'modules/indexing-guide/examples', 'modules/query-guide/examples']
+        }
+    }
+}
+
+dependencies {
+    // For the SolrJ examples
+    testImplementation project(":solr:core")
+    testImplementation project(":solr:solrj")
+    testImplementation project(":solr:test-framework")
+    testImplementation 'junit:junit'
+}
+
+// Copy all the test resource files from SolrJ to the build/resources/test directory
+// of the examples so we can avoid duplication of the test resource files like
+// schemas and SolrConfigs.
+task copySolrjTestResources(type: Copy) {
+    from(project(':solr:solrj').sourceSets.test.resources.srcDirs) {
+        exclude '**/*.java'
+    }
+    into sourceSets.test.output.resourcesDir
+}
+
+tasks.processTestResources.configure {
+    dependsOn copySolrjTestResources
+}