how to rename android package name using gradle on cmd? -

i want rename package name using gradle on cmd.because have multiple project customization , change package name using ide difficult change each package name separately.please give me solution.thanks in advance

 apply plugin: 'com.android.application'     apply plugin: 'maven'      android {         compilesdkversion 21         buildtoolsversion "23.0.0 rc2"           sourcesets {             defaultconfig {                 applicationid "com.appbell.restaurant.genericresto"                 minsdkversion 14                 targetsdkversion 19                 compileoptions {                     sourcecompatibility javaversion.version_1_7                     targetcompatibility javaversion.version_1_7                 }              }             main {                 manifest.srcfile 'src\\main\\androidmanifest.xml'                 println('android'+manifest.srcfile)             }          }          buildtypes {             release {                 minifyenabled true                 proguardfiles getdefaultproguardfile('proguard-android.txt'), 'proguard-rules.txt'             }         }     }      task changepackage{         replaceinmanifest("com.appbell.restaurant.example","com.appbell.imenu4u")     }      buildscript {         repositories {             mavencentral()         }         dependencies {             // make sure @ least 0.10.+             classpath 'com.android.tools.build:gradle:1.0.+'         }     }      task appstart(type: exec, dependson: 'installdebug') {         // linux         //commandline 'adb', 'shell', 'am', 'start', '-n', 'com.example/.myactivity'         // windows          commandline 'cmd', '/c', 'adb', 'shell', 'am', 'start', '-n', 'com.appbell.restaurant.genericresto/com.appbell.and.resto.and.ui.splashactivity'     }      dependencies {         compile project(':facebook')         compile project(':stripe')         compile 'com.google.android.gms:play-services:+'         compile 'com.android.support:appcompat-v7:21.0.3'         compile files('libs/mobileappclasses.jar')         compile files('libs/pgsdk.jar')     }      def replaceinmanifest(fromstring, tostring) {         def manifestfile = "c:\\users\\ntin gorle\\androidstudioprojects\\myapplication\\restoappnew\\src\\main\\androidmanifest.xml"         def updatedcontent = new file(manifestfile).gettext('utf-8').replaceall(fromstring, tostring)         new file(manifestfile).write(updatedcontent, 'utf-8')     } 

i code package name change not reflect in .java file.please tell me how change in .java classes.