How can I store the HashMap <String, String>?

You have to create Entity with String-primary-key and String-proerty for value:

Entity mapEntity = schema.addEntity("Map");
mapEntity.addStringProperty("key").primaryKey();
mapEntity.addStringProperty("value");

      

        
        
        
      

    

Maybe some other attributes are needed for properties (depending on your needs) like unique, notNull.

If you want to keep your map inside an object, it is not that easy:

Basically you create an entity like this to hold all the Maps:

Entity mapEntity = schema.addEntity("Map");
mapEntity.addLongProperty("id").primaryKey().autoIncrement();
mapEntity.addStringProperty("key").unigue().notNull();
mapEntity.addStringProperty("value");

      

        
        
        
      

    

and then create a relationship toOne()

or toMany()

to link to the corresponding map.

PS Perhaps you should choose other names besides key

and value

. These variable names are commonly used and can create conflicts in greendao.