add classpath jar creation for windows os

closes jhipster#9713

generators/server/templates/build.gradle.ejs

@@ -16,7 +16,9 @@
  See the License for the specific language governing permissions and
  limitations under the License.
 -%>
-buildscript {
+import org.gradle.internal.os.OperatingSystem
+
+buildscript {9713
     repositories {
         mavenLocal()
         mavenCentral()
@@ -96,6 +98,26 @@ eclipse {
     }
 }
 
+// See https://virgo47.wordpress.com/2018/09/14/classpath-too-long-with-spring-boot-and-gradle/ for details
+// https://github.com/jhipster/generator-jhipster/issues/9713
+if (OperatingSystem.current().isWindows()) {
+    task classpathJar(type: Jar) {
+        inputs.files sourceSets.main.runtimeClasspath
+
+        archiveName = "runboot-classpath.jar"
+        doFirst {
+            manifest {
+              def classpath = sourceSets.test.runtimeClasspath.files
+              attributes "Class-Path": classpath.collect {f -> f.toURI().toString()}.join(" ")
+            }
+        }
+    }
+
+    bootRun {
+        classpath = classpathJar.outputs.files
+    }
+}
+
 defaultTasks "bootRun"
 
 group = "<%= packageName %>"