FooEntity.java

public class FooEntity {

    String foo;
    String bar;

    public String getFoo() {
        return foo;
    }

    public void setFoo(String foo) {
        this.foo = foo;
    }

    public String getBar() {
        return bar;
    }

    public void setBar(String bar) {
        this.bar = bar;
    }
}

FooList.java

@JsonRootName("myRootName")
public class FooList {

    public List<FooEntity> fooList;

    public FooList() {
        this.fooList = new ArrayList<FooEntity>();
    }

    public void add(FooEntity fooEntity) {
        this.fooList.add(fooEntity);
    }

    @JsonValue
    public List<FooEntity> getFooList() {
        return fooList;
    }

    public void setFooList(List<FooEntity> fooList) {
        this.fooList = fooList;
    }
}

WrappingTest.java

public class WrappingTest {
    @Test
    public void fooListToJson() throws IOException {
        FooList fooList = new FooList();


        FooEntity fooEntity1 = new FooEntity();
        fooEntity1.setBar("fooEntity1 bar value");
        fooEntity1.setFoo("fooEntity1 foo value");

        FooEntity fooEntity2 = new FooEntity();
        fooEntity2.setBar("fooEntity2 bar value");
        fooEntity2.setFoo("fooEntity2 foo value");

        fooList.add(fooEntity1);
        fooList.add(fooEntity2);

        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(SerializationConfig.Feature.WRAP_ROOT_VALUE, true);
        StringWriter stringWriter = new StringWriter();
        final JsonGenerator jsonGenerator = mapper.getJsonFactory().createJsonGenerator(stringWriter);

        mapper.writeValue(jsonGenerator, fooList);

        System.out.println(stringWriter.toString());
    }
}