java - How do I run selenium test one after the other on multiple browser -

not sure going wrong, trying run same set of test 1 after other on multiple browser.

testng.xml

<suite  name="selenium tests"   parallel="false" thread-count="5"> <listeners>     <listener class-name="ww5.listener.listener" /> </listeners> <test name="chrome" preserve-order="true">    <parameter name="browser" value="chrome"/>    <classes>         <class name="ww5.testcases.version.version" ></class>          <class name="ww5.testcases.loginsuite.logintest" ></class>          <class name="ww5.testcases.loginsuite.logouttest" ></class>    </classes> </test>  <test name="firefox" preserve-order="true">    <parameter name="browser" value="firefox"/>     <classes>         <class name="ww5.testcases.version.version" ></class>          <class name="ww5.testcases.loginsuite.logintest" ></class>          <class name="ww5.testcases.loginsuite.logouttest" ></class>      </classes> </test> </suite> 

when run this, test excuted on chrome, how make excute on firefox after finish excuting on chrome.

openbrowser.java

@parameters ({"browser"})         @beforeclass         public void launchbrowser(string browser) throws exception {             //initlogs(this.getclass());             initconfigurations();             if (driver == null) {             desiredcapabilities cap = null;             if(browser.equalsignorecase("firefox"))             {                 cap = desiredcapabilities.firefox();                 cap.setbrowsername("firefox");                 //cap.setplatform(org.openqa.selenium.platform.windows);                 }             if(browser.equalsignorecase("internet explorer"))             {                 cap = desiredcapabilities.internetexplorer();                 cap.setbrowsername("internet explorer");                 cap.setplatform(org.openqa.selenium.platform.any);                 }             if(browser.equalsignorecase("chrome"))             {                 cap = desiredcapabilities.chrome();                 cap.setbrowsername("chrome");                 cap.setplatform(org.openqa.selenium.platform.any);                 }             driver = new remotewebdriver(new url("http://localhost:4444/wd/hub"), cap);             driver.manage().window().maximize();             driver.manage().timeouts().implicitlywait(30, timeunit.seconds);             wait = new webdriverwait(driver,30);             }         } 

replace <suite name="selenium tests" parallel="false" thread-count="5">

<suite name="selenium tests" parallel="tests" thread-count="2">

all other things seems fine. refer this more info.

edit:

i understood problem incorrectly. issue not able run test sequentially due if (driver == null). mean test run first time driver null, after due driver definition may not null , hence not create capability. so, if remove it, tests should run fine.