title: Need suggestion to swap key and value of complex json
body: <p>I have the below json</p>
  
  <pre><code>{  
     "Roles":[  
        {  
           "January":[  
              {  
                 "CN":[  
                    "GoogleCnFeatureOwner",
                    "GoogleCnAnalyst",
                    "SupportAnalyst",
                    "AdminCn"
                 ]
              },
              {  
                 "EU":[  
                    "GoogleEuFeatureOwner",
                    "GoogleEuAnalyst",
                    "SupportAnalyst",
                    "AdminEu"
                 ]
              },
              {  
                 "NA":[  
                    "GoogleNaFeatureOwner",
                    "GoogleNaAnalyst",
                    "SupportAnalyst",
                    "AdminNa"
                 ]
              }
           ]
        },
        {  
           "February":[  
              {  
                 "CN":[  
                    "AbcCnFeatureOwner",
                    "AbcCnAnalyst",
                    "SupportAnalyst",
                    "AdminCn"
                 ]
              },
              {  
                 "EU":[  
                    "AbcEuFeatureOwner",
                    "AbcEuAnalyst",
                    "SupportAnalyst",
                    "AdminEu"
                 ]
              },
              {  
                 "NA":[  
                    "AbcNaFeatureOwner",
                    "AbcNaAnalyst",
                    "SupportAnalyst",
                    "AdminNa"
                 ]
              }
           ]
        },
        {  
           "March":[  
              {  
                 "CN":[  
                    "YahooCnFeatureOwner",
                    "SupportAnalyst",
                    "AdminCn",
                    "UserCn"
                 ]
              },
              {  
                 "NA":[  
                    "YahooNaFeatureOwner",
                    "SupportAnalyst",
                    "AdminNa",
                    "UserNa"
                 ]
              }
           ]
        }
     ]
  }
  </code></pre>
  
  <p>I'm trying to implement a method in java to parse the above json and swap the key with value and create a collective json like below. </p>
  
  <pre><code>    {
      "WifiCnFeatureOwner": [{
          "CN": ["January"]
      }],
      "ItSupportAnalyst": [{
          "CN": ["January", "February", "March"]
      }, {
          "EU": ["January", "February"]
      }, {
          "NA": ["January", "February", "March"]
      }]
  }
  </code></pre>
  
  <p>I'm using org.json APIs to start with. 
  Please suggest some best approach to achieve the conversion effectively (without Guava BiMap). I'll post the code once completed anyway. </p>