What the best way to persist data in Java application without SQL or any Database Sever?

I wants create a desktop app that need to store data. This app can be used in various pc's. So, I don't want install sql server and more applications to make this. I want just create a file with all data that is stored, making backup easier and have a fast installation. I thought use a JSON or XML file, or Excel (.xmls), but this appears hard to execute a searchs, or other operation. So, before implements this I want a opinion.

You can use com.typesafe.config or SQLite. It depend on data, that you must store. Another solution is to serialize your data class to XML\JSON with GSON or xstream

Gson example:

public static class Entity {
    volatile int id;
    String name;
    transient long random;

    public Entity(int id, String name) {
        this.id = id;
        this.name = name;
    }
}
//Create new entity
Entity entity = new Entity(100, "name");
entity.random = 1234;

//Serialize to JSON. Then you can save string to file
String json = gson.toJson(entity); // {"id":100,"name":"name"}
// On application start you can deserialize your entity from file
Entity read = gson.fromJson(json, Entity.class);