Cannot cast object 'url' with class 'java.lang.String' to class 'int' Gradle Java

I am trying to read gradle.properties into my build.gradle. I have defined some argument values in the property file and now wanted to pass these values to the argument. So that it will pass this argument value to my main methode. But I am getting the following error:

group 'org.name'
version '1.0-SNAPSHOT'
apply plugin: 'java'
apply plugin: 'groovy'
sourceCompatibility = 1.8
repositories {
    mavenCentral()
}

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.12'
    compile "joda-time:joda-time:2.2"
    // https://mvnrepository.com/artifact/mysql/mysql-connector-java
    compile group: 'mysql', name: 'mysql-connector-java', version: '5.1.6'
    // https://mvnrepository.com/artifact/org.dbunit/dbunit
    compile group: 'org.dbunit', name: 'dbunit', version: '2.4.7'
    compile "org.slf4j:slf4j-simple:1.7.9";
}
task runApp(type: JavaExec) {
    classpath = sourceSets.main.runtimeClasspath
    main = 'ExportDatatoXML'
    println url
    println username
    println password
    println folderPath
    // arguments to pass to the application
    args  
     [project.property('url'),project.property('username'),
      project.property('password'),project.property('folderPath')]
 }

This is my build.gradle file

gradle.properties file is:

url =jdbc:mysql://127.0.0.1:3306/name
username =root
password =name
folderPath =C:/Users/name/Desktop/DataBase/

Error is following:

FAILURE: Build failed with an exception.

* Where:
 Build file 'C:\Users\name\IdeaProjects\HelloWorld\build.gradle' line: 36

* What went wrong:
A problem occurred evaluating root project 'AI'.
      > Cannot cast object 'jdbc:mysql://127.0.0.1:3306/name' with class 
    'java.lang.String' to class 'int'

   * Try:
       Run with --stacktrace option to get the stack trace. Run with --info 
      or --debug option to get more log output.

      BUILD FAILED

     Total time: 12.448 secs
     Cannot cast object 'jdbc:mysql://127.0.0.1:3306/name' with class 
    'java.lang.String' to class 'int'
   13:01:41: External task execution finished 'build'