Merging multiple XML files using Java

I have a code to merge two xml files but the results i expected was different.

XML 1:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<testsuite errors="0" failures="0" name="unit.qa.fm" tests="14" time="3182.09">
<properties/>
<testcase classname="com.ca.clarity.unit.financial.transaction.CBKRuleForAllFTP42249QAUTest" name="invoiceAdjustments" testCaseID="42249" time="175.548"/>
<testcase classname="com.ca.clarity.unit.financial.transaction.CreateWIPAdjustmentChangingRateReflectInInvoice42207QAUTest" name="invoiceAdjustments42207" testCaseID="42207" time="171.971"/>
</testsuite>

XML 2:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<testsuite errors="0" failures="0" name="unit.qa.fm" tests="10" time="1647.807">
<properties/>
<testcase classname="com.ca.clarity.unit.financial.setup.CheckDepartmentAndDepartmentOBSAreInSync58786QAUTest" name="CheckDeptAndDeptOBSAreInSync" testCaseID="58786" time="27.132"/>
<testcase classname="com.ca.clarity.unit.financial.setup.DepartmentXogQAUTest" name="validateDepartmentXogIn" testCaseID="52082" time="11.097"/>
</testsuite>

Expected result:

Actual I am getting

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<testsuite errors="0" failures="0" name="unit.qa.fm" tests="14" time="3182.09">
<properties/>
<testcase classname="com.ca.clarity.unit.financial.transaction.CBKRuleForAllFTP42249QAUTest" name="invoiceAdjustments" testCaseID="42249" time="175.548"/>
<testcase classname="com.ca.clarity.unit.financial.transaction.CreateWIPAdjustmentChangingRateReflectInInvoice42207QAUTest" name="invoiceAdjustments42207" testCaseID="42207" time="171.971"/>
 <testcase classname="com.ca.clarity.unit.financial.setup.CheckDepartmentAndDepartmentOBSAreInSync58786QAUTest" name="CheckDeptAndDeptOBSAreInSync" testCaseID="58786" time="27.132"/>
 <testcase classname="com.ca.clarity.unit.financial.setup.DepartmentXogQAUTest" name="validateDepartmentXogIn" testCaseID="52082" time="11.097"/>
 </testsuite><?xml version="1.0" encoding="UTF-8" standalone="no"?><testsuite errors="0" failures="0" name="unit.qa.fm" tests="10" time="1647.807">
<properties/>
<testcase classname="com.ca.clarity.unit.financial.setup.CheckDepartmentAndDepartmentOBSAreInSync58786QAUTest" name="CheckDeptAndDeptOBSAreInSync" testCaseID="58786" time="27.132"/>
<testcase classname="com.ca.clarity.unit.financial.setup.DepartmentXogQAUTest" name="validateDepartmentXogIn" testCaseID="52082" time="11.097"/>
</testsuite>

Can anyone help me to add only testcase node to existing XML file not the whole content.

Thanks,