Version 1:
private static void setProperties() {
	player
		.add(NamedValue.of("Name", "Brian"))
		.add(NamedValue.of("Durability", 73.5))
		.add(NamedValue.of("Damage", 3.44))
		.add(NamedValue.of("Enchantability", 1.2))
		.add(NamedValue.of("Hunger", 10))
		.add(NamedArray.of("Inventory",
			NamedObject.of("Bastard Sword", NamedValue.of("Durability", 85.2), NamedValue.of("Enchantability", 13.75), NamedValue.of("Damage", 12), NamedObject.of("Enchantments", NamedValue.of("Keening", 1), NamedValue.of("Sunder", 1), NamedValue.of("Wraithguard", 1)), NamedObject.of("Requirements", NamedValue.of("Strength", 35), NamedValue.of("Wisdom", 15))),
			NamedObject.of("Tower Shield", NamedValue.of("Durability", 85.2), NamedValue.of("Enchantability", 13.75), NamedValue.of("Damage", 12), NamedObject.of("Enchantments", NamedValue.of("Keening", 1), NamedValue.of("Sunder", 1), NamedValue.of("Wraithguard", 1)), NamedObject.of("Requirements", NamedValue.of("Strength", 35), NamedValue.of("Wisdom", 15))),
			NamedObject.of("Golden Scepter", NamedValue.of("Durability", 85.2), NamedValue.of("Enchantability", 13.75), NamedValue.of("Damage", 12), NamedObject.of("Enchantments", NamedValue.of("Keening", 1), NamedValue.of("Sunder", 1), NamedValue.of("Wraithguard", 1)), NamedObject.of("Requirements", NamedValue.of("Strength", 35), NamedValue.of("Wisdom", 15)))));
}

Version 2:
private static void setProperties() {
	player
		.add(NamedValue.of("Name", "Brian"))
		.add(NamedValue.of("Durability", 73.5))
		.add(NamedValue.of("Damage", 3.44))
		.add(NamedValue.of("Enchantability", 1.2))
		.add(NamedValue.of("Hunger", 10))
		.add(NamedArray.of("Inventory",
			NamedObject.of("Bastard Sword",
				NamedValue.of("Durability", 85.2),
				NamedValue.of("Enchantability", 13.75),
				NamedValue.of("Damage", 12),
				NamedObject.of("Enchantments",
					NamedValue.of("Keening", 1),
					NamedValue.of("Sunder", 1),
					NamedValue.of("Wraithguard", 1)),
				NamedObject.of("Requirements",
					NamedValue.of("Strength", 35),
					NamedValue.of("Wisdom", 15)
				)
			),
			NamedObject.of("Tower Shield",
				NamedValue.of("Durability", 85.2),
				NamedValue.of("Enchantability", 13.75),
				NamedValue.of("Damage", 12),
				NamedObject.of("Enchantments",
					NamedValue.of("Keening", 1),
					NamedValue.of("Sunder", 1),
					NamedValue.of("Wraithguard", 1)),
				NamedObject.of("Requirements",
					NamedValue.of("Strength", 35),
					NamedValue.of("Wisdom", 15)
				)
			),
			NamedObject.of("Golden Scepter",
				NamedValue.of("Durability", 85.2),
				NamedValue.of("Enchantability", 13.75),
				NamedValue.of("Damage", 12),
				NamedObject.of("Enchantments",
					NamedValue.of("Keening", 1),
					NamedValue.of("Sunder", 1),
					NamedValue.of("Wraithguard", 1)),
				NamedObject.of("Requirements",
					NamedValue.of("Strength", 35),
					NamedValue.of("Wisdom", 15)
				)
			)
		)
	);
}

JSON Output:
{  
   "Player":{  
      "Name":"Brian",
      "Durability":73.5,
      "Damage":3.44,
      "Hunger":10,
      "Inventory":[  
         {  
            "Bastard Sword":{  
               "Durability":85.2,
               "Enchantability":13.75,
               "Damage":12,
               "Enchantments":{  
                  "Keening":1,
                  "Sunder":1,
                  "Wraithguard":1
               },
               "Requirements":{  
                  "Strength":35,
                  "Wisdom":15
               }
            }
         },
         {  
            "Tower Shield":{  
               "Durability":85.2,
               "Enchantability":13.75,
               "Damage":12,
               "Enchantments":{  
                  "Keening":1,
                  "Sunder":1,
                  "Wraithguard":1
               },
               "Requirements":{  
                  "Strength":35,
                  "Wisdom":15
               }
            }
         },
         {  
            "Golden Scepter":{  
               "Durability":85.2,
               "Enchantability":13.75,
               "Damage":12,
               "Enchantments":{  
                  "Keening":1,
                  "Sunder":1,
                  "Wraithguard":1
               },
               "Requirements":{  
                  "Strength":35,
                  "Wisdom":15
               }
            }
         }
      ]
   }
}