Conditional signing.

Author: kishorenc

build.gradle

@@ -1,5 +1,9 @@
-apply plugin: 'java'
-apply plugin: 'idea'
+plugins {
+    id 'java-library'
+    id 'signing'
+    id 'maven-publish'
+    id('io.github.gradle-nexus.publish-plugin') version '1.1.0'
+}
 
 repositories {
     mavenCentral()
@@ -112,6 +116,8 @@ publishing {
     }
 }
 
-signing {
-    sign publishing.publications.mavenJava
+if (project.hasProperty("signing.keyId")) {
+    signing {
+        sign publishing.publications.mavenJava
+    }
 }