diff --git a/build.gradle b/build.gradle
index 47527c02be..2e8a4b6919 100644
--- a/build.gradle
+++ b/build.gradle
@@ -288,7 +288,7 @@ subprojects {
 
 
         // Specifying the local via system properties did not work, so we set them this way
-        jvmArgs << [
+        jvmArgs += [
             '-Djava.awt.headless=true',
             '-Djavax.xml.stream.XMLInputFactory=com.sun.xml.internal.stream.XMLInputFactoryImpl',
             "-Dversion.id=${project.version}",
diff --git a/poi-excelant/build.gradle b/poi-excelant/build.gradle
index 0c0bb935d4..d61d41267b 100644
--- a/poi-excelant/build.gradle
+++ b/poi-excelant/build.gradle
@@ -121,7 +121,7 @@ sourcesJar {
 task testJar(type: Jar, dependsOn: [ testClasses, compileTest9 ] ) {
     destinationDirectory = file("../build/dist/maven/${project.archivesBaseName}-tests")
 
-    classifier 'tests'
+    setArchiveClassifier 'tests'
     // ignore second module-info.class from main
     duplicatesStrategy = 'exclude'
 
diff --git a/poi-integration/build.gradle b/poi-integration/build.gradle
index f9967fc2dd..4941a232d7 100644
--- a/poi-integration/build.gradle
+++ b/poi-integration/build.gradle
@@ -128,7 +128,7 @@ jar {
 task testJar(type: Jar, dependsOn: [ testClasses, compileTest9 ] ) {
     destinationDirectory = file("../build/dist/maven/${project.archivesBaseName}-tests")
 
-    classifier 'tests'
+    setArchiveClassifier 'tests'
     // ignore second module-info.class from main
     duplicatesStrategy = 'exclude'
 
diff --git a/poi-ooxml-full/build.gradle b/poi-ooxml-full/build.gradle
index 01e5d47d91..81f38a8e0e 100644
--- a/poi-ooxml-full/build.gradle
+++ b/poi-ooxml-full/build.gradle
@@ -126,7 +126,7 @@ task generate_beans(dependsOn: copy_xsds) {
 }
 
 task sourceJar(type: Jar) {
-    classifier 'sources'
+    setArchiveClassifier 'sources'
     from sourceSets.main.allJava
 }
 
diff --git a/poi-ooxml/build.gradle b/poi-ooxml/build.gradle
index d03752bdb8..bb54b14bbb 100644
--- a/poi-ooxml/build.gradle
+++ b/poi-ooxml/build.gradle
@@ -198,7 +198,7 @@ jar {
 task testJar(type: Jar, dependsOn: testClasses) {
     destinationDirectory = file("../build/dist/maven/${project.archivesBaseName}-tests")
 
-    classifier 'tests'
+    setArchiveClassifier 'tests'
     // ignore second module-info.class from main
     duplicatesStrategy = 'exclude'
 
diff --git a/poi-scratchpad/build.gradle b/poi-scratchpad/build.gradle
index 60efe68b22..7f08037587 100644
--- a/poi-scratchpad/build.gradle
+++ b/poi-scratchpad/build.gradle
@@ -101,7 +101,7 @@ jar {
 task testJar(type: Jar, dependsOn: testClasses) {
     destinationDirectory = file("../build/dist/maven/${project.archivesBaseName}-tests")
 
-    classifier 'tests'
+    setArchiveClassifier 'tests'
     // ignore second module-info.class from main
     duplicatesStrategy = 'exclude'
 
diff --git a/poi/build.gradle b/poi/build.gradle
index c2f60e24a0..649251f975 100644
--- a/poi/build.gradle
+++ b/poi/build.gradle
@@ -128,7 +128,7 @@ jar {
 task testJar(type: Jar, dependsOn: [ testClasses, compileTest9 ]) {
     destinationDirectory = file("../build/dist/maven/${project.archivesBaseName}-tests")
 
-    classifier 'tests'
+    setArchiveClassifier 'tests'
     // ignore second module-info.class from main
     duplicatesStrategy = 'exclude'