Добавил примеры частоиспользуемых штук

README.md

@@ -1,2 +1,85 @@
 # JPA-examples
 
+### Entity annotation
+
+```java
+
+@Entity
+@Table
+public final class MyEntityClass {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private long id;
+
+    @Column
+    private float primitiveField;
+
+    @Column
+    private String primitiveField2;
+
+}
+```
+
+### References to another entities
+
+```java
+
+@Entity
+@Table
+public final class AnotherEntity {
+    //...
+    @ManyToMany(fetch = FetchType.EAGER)
+    @JoinColumn(name = "my_entity_id", nullable = false)
+    private Collection<MyEntityClass> entities;
+}
+```
+
+### Collection of primitives
+
+```java
+//...
+public final class AnotherEntity {
+    //...
+    @ElementCollection(fetch = FetchType.EAGER)
+    private Set<String> stringSet;
+}
+
+```
+
+### Map field as another data type
+
+```java
+
+//...
+public final class AnotherEntity {
+    //...
+    @Column
+    @JSONProperty
+    @Convert(converter = CustomConverter.class)
+    private CustomType settings;
+}
+
+public class CustomType {
+    //...
+}
+
+/*
+        Convert custom type to string and vise versa
+ */
+@Converter
+public static class CustomConverter implements AttributeConverter<CustomType, String> {
+
+    @Override
+    public String convertToDatabaseColumn(CustomType customType) {
+        // return ...
+    }
+
+    @Override
+    public CustomType convertToEntityAttribute(String dbData) {
+        // return ...
+    }
+}
+
+
+
+```