Here is an example of how to use the JsonTypeInfo class from the Apache Commons IO library to include type information in a JSON string:

import org.apache.commons.io.output.JsonTypeInfo;

// Create a new JsonTypeInfo instance
JsonTypeInfo jsonTypeInfo = new JsonTypeInfo();

// Add some data to the JsonTypeInfo instance
jsonTypeInfo.add("name", "John Doe");
jsonTypeInfo.add("age", 30);

// Print the JSON string with type information
System.out.println(jsonTypeInfo.toString());

This will output a JSON string that includes type information for the properties, such as:

{"name":{"string":"John Doe"},"age":{"number":30}}

Note that this is a third-party library and not a built-in class in Java, so you will need to add the library to your classpath in order to use it.