title: UUID random number generation
body: <p>I am using UUID Random number as a primary key of Object when i save object in Database. So this generated UUID number should be unique. This way i got random number. </p>
  
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  <pre><code>final String UUIDUserToken = UUID.randomUUID().toString()  
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  <p>Can this generated number unique for any generated number? </p>
  
  <p>Give me idea.</p>