Why value of JSON changes “:” to “=” in Helper class

Question

The template is created in Handlebars JS. and to process in Java jknack handlebars is used. I wrote helper class to assign value in a variable through enum syntax. I got inspiration from enum NumberHelper and write my own enum VarHelper. Here is the "Var" code

{{ var "$a" jsonObj }}

var { 
@Override public CharSequence safeApply(final String variableName, final Options options) throws IOException { 
  System.out.println( options.params[0]); options.context.data(variableName, options.params[0]); return null; 
} 
};

I expect options.params[0] value should be {name : john}, but the actual output is {name=john}