diff --git a/buildSrc/src/main/groovy/org/jabref/build/antlr/AntlrTask.groovy b/buildSrc/src/main/groovy/org/jabref/build/antlr/AntlrTask.groovy
index c31aefc1d19..5bfa700da9c 100644
--- a/buildSrc/src/main/groovy/org/jabref/build/antlr/AntlrTask.groovy
+++ b/buildSrc/src/main/groovy/org/jabref/build/antlr/AntlrTask.groovy
@@ -1,5 +1,6 @@
 package org.jabref.build.antlr
 
+import org.gradle.api.Task
 import org.gradle.api.tasks.JavaExec
 import org.gradle.api.tasks.TaskAction
 
@@ -12,6 +13,7 @@ class AntlrTask extends JavaExec {
     private String inputFile = ""
     private String outputDir = ""
     private String javaPackage = ""
+    private AntlrCommandLine commandLine
 
     AntlrTask() {
         project.configurations {
@@ -20,13 +22,19 @@ class AntlrTask extends JavaExec {
         }
     }
 
+    @Override
+    Task configure(Closure closure) {
+        commandLine = antlr.newInstance(this)
+
+        setMain(commandLine.main)
+
+        return super.configure(closure)
+    }
+
     @TaskAction
     @Override
     void exec() {
-        AntlrCommandLine commandLine = antlr.newInstance(this)
-
-        main = commandLine.main
-        classpath = commandLine.classpath
+        classpath(commandLine.classpath)
         args = commandLine.arguments
 
         super.exec()
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 490fda8577d..62d4c053550 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index a4b4429748d..bb8b2fc26b2 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.3-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.5.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists