While Starting Confluence 6.1.0 i am getting error : [Fatal Error] server.xml:1:1: Content is not allowed in prolog.

[Sumit Sumit]

Below is snip of logs while starting confluence 6.1.0 : 

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[confluence@localhost bin]$ sh start-confluence.sh

To run Confluence in the foreground, start the server with start-confluence.sh -fg
executing as current user
If you encounter issues starting up Confluence, please see the Installation guide at http://confluence.atlassian.com/display/DOC/Confluence+Installation+Guide

Server startup logs are located in /opt/atlassian/confluence/logs/catalina.out
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Using Java: /opt/atlassian/confluence/jre//bin/java
[Fatal Error] server.xml:1:1: Content is not allowed in prolog.
[Fatal Error] server.xml:1:1: Content is not allowed in prolog.
Content is not allowed in prolog.
[Fatal Error] server.xml:1:1: Content is not allowed in prolog.
Content is not allowed in prolog.
2017-03-22 11:40:25,159 INFO [main] [atlassian.confluence.bootstrap.SynchronyProxyWatchdog] The Confluence context path is empty. No further action is required.

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catalina.out logs : 

[confluence@localhost logs]$ cat catalina.out
Error: Could not find or load main class is
[confluence@localhost logs]$

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[Sumit Sumit]

By restoring the same version with backup file, error is resolved