title: How to deserialize nested JSON array into a Map using Java's Jackson library?
body: <p>I have a structure like so:</p>
  
  <pre><code>{
      "name": "user",
      "values":[["0.00207760","18.48000000"],["0.00207740","40.00000000"],["0.00207710","2.26000000"]]
  }
  </code></pre>
  
  <p>I'd like to deserialize into a class like so using the popular Jackson library:</p>
  
  <pre><code>public class Values {
  
      public String name;
  
      public Map&lt;BigDecimal, BigDecimal&gt; values = new HashMap&lt;&gt;();
  
  }
  </code></pre>
  
  <p>Where each entry in the <code>values</code> property becomes a key/value entry in the class' map.</p>
  
  <p>However, if I attempt a simple deserialization with Jackson I get this error:</p>
  
  <pre><code>com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.util.TreeMap&lt;java.lang.Object,java.lang.Object&gt;` out of START_ARRAY token
   at [Source: (String)"{"name": "user","values":[["0.00207760","18.48000000"],["0.00207740","40.00000000"],["0.00207710","2.26000000"]]...
      at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)
      at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1442)
      at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1216)
      ...
  </code></pre>
  
  <p><strong>How can this be accomplished using Jackson?</strong></p>
  
  <p>Thanks!</p>
  
  <p>Eduardo</p>