September 29, 2014

LocalDate java 8 Custom Serializer Jackson JSON Example

In this previous example we use serialize and deserialize classes provided by a Jackson third party datatype. For more control over the date formatting you can opt to create your own serialize and deserialize classes.

WildFly 8.1.0 uses Jackson 2.3.2 so we can add the following dependencies to the pom with a scope of provided:
Then on the LocalDate property of your bean add the following annotations:
public class MyBean {

    @JsonDeserialize(using = JsonDateDeserializer.class)
    @JsonSerialize(using = JsonDateSerializer.class)
    private LocalDate date;
    public LocalDate getDate() {
        return date;

    private void setDate(LocalDate date) { = date;
Now create the custom JsonDateSerializer:
public class JsonDateSerializer extends JsonSerializer<LocalDate> {

    private final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    public void serialize(LocalDate date, JsonGenerator generator,
            SerializerProvider provider) throws IOException,
            JsonProcessingException {

        String dateString = date.format(formatter);
And now the custom JsonDateDeserializer:
public class JsonDateDeserializer extends JsonDeserializer<LocalDate> {

    public LocalDate deserialize(JsonParser jp, DeserializationContext ctxt)
            throws IOException, JsonProcessingException {

        ObjectCodec oc = jp.getCodec();
        TextNode node = (TextNode) oc.readTree(jp);
        String dateString = node.textValue();

        Instant instant = Instant.parse(dateString);
        LocalDateTime dateTime = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
        LocalDate date = LocalDate.of(dateTime.getYear(), dateTime.getMonth(), dateTime.getDayOfMonth());
        return date;

NOTE: The package names have changed in Jackson 2. When you use the Jackson annotations make sure you import the one from the com.fasterxml.jackson.databind.annotation.* package and not the ones from the* package. If you import the latter, your annotations will be ignored. WildFly 8 does not load the classes from the 1.9.2 jackson module.

September 23, 2014

Java 8 LocalDate with Jackson Serialize and Deserialize Example - RESTful WS

Although I having using Joda Time for years, it is now time to migrate over to the Java 8 Date and Time API (JSR310), and make use of the new LocalDate and LocalTime classes.

WildFly 8.1.0 uses Jackson 2.3.2 which does not know how to (de)serialize the JSR310 Date Time classes. So in order to use the Date and Time API we need to add a Jackson third party datatype dependency to our pom:
Then to deserialize your LocalDate add the @JsonDeserialize annotation and use the LocalDateDeserializer:
public class MyRestResource {

    @JsonDeserialize(using = LocalDateDeserializer.class)
    public LocalDate get() {
To serialize your LocalDate add @JsonSerialize annotation and use the LocalDateSerializer:
@JsonSerialize(using = LocalDateSerializer.class)

To create your own serializer/deserializer check this example, which shows you how you can format the date.

July 17, 2014

Save Session State Between Redeploys - Developing on WildFly

When developing, it is often convenient to save session state between redeploys or server restarts. To enable this feature in WildFly 8 you need to add the persistent-sessions element to your configuration file (within the undertow subsystem).

<servlet-container name="default">
    <persistent-sessions path="session" relative-to="jboss.server.temp.dir"/>
By specifying the relative-to attribute, the session will only be persistent across redeploys and not across server restarts.

This feature works in WildFly 8.2.0.CR1 and greater.

You can also achieve session passivation, when you are using a non-ha profile, by adding <distributable/> to your web.xml (for those using WildFly 8.1.0 or less).

April 22, 2014

How to use Java 8 with WildFly 8 and Eclipse


1. Download and install Java 8
2. Download and install WildFly 8
4. Download and install Eclipse Luna (4.4) (or Kepler 4.3 patched for Java 8)

Configure WildFlys VM args

Before starting WildFly, update your standalone.conf, or domain.conf by replacing the following JVM argument:

The removal of the MaxPermSize property will prevent VM warnings from showing in WildFlys startup logs.

The -XX:PermSize and -XX:MaxPermSize VM arguments are now redundant as PermGen has been replaced in Java 8 with Metaspace. The new VM arguments are -XX:MetaspaceSize and -XX:MaxMetaspaceSize.
Note that the Metaspace data will sit in your computers native memory. For a rundown on the differences between PermGen and Metaspace, check out this blog.

Installing JBoss Tools

In Eclipse Luna (4.4), go to Help > Eclipse Marketplace and type 'JBoss Tools', and click go.  Make sure that you select and install the version that matches your Eclipse install. In this example it is JBoss Tools (Luna) 4.2.0.Beta1.

Click install.

On the next screen you can select which components of JBoss Tools you want to install. To install just the server adapter, select 'JBossAS Tools'. Agree to the terms and click OK. Restart Eclipse when you are given the option to do so.

Now choose File > New > Server. Expand the 'JBoss Community' node and select the option 'WildFly 8'.

Click Next, and Next again

Make sure you select your installed Java 8 JRE, and that you point the home directory to that of your WildFly root directory (As shown below). Click finish.

Finally, in your servers view (Window > Show View > Servers), Select the WildFly Server, right click and select start. All being well, WildFly should now start up.

Finally to configure your WildFly server settings, double click on the WildFly server in your servers view. The screen above should be displayed, allowing you to configure your server/deployment properties.