CREATE TABLE IF NOT EXISTS `tbltest` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(25) COLLATE utf8_unicode_ci NOT NULL,
  `isSomething` tinyint(1) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=3 ;

INSERT INTO `tbltest` (`id`, `name`, `isSomething`) VALUES
(1, 'John Doe', 1),
(2, 'Jane Doe', 0);

import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "tbltest")
public class Test implements Serializable
{
	private static final long serialVersionUID = 1L;

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Basic(optional = false)
	@Column(name = "id", nullable = false)
	private Integer id;

	@Basic(optional = false)
	@Column(name = "name", nullable = false, length = 25)
	private String name;

	@Basic(optional = false)
	@Column(name = "isSomething", nullable = false)
	private boolean isSomething;

	public Test()
	{
	}

	public Test(Integer id)
	{
		this.id = id;
	}

	public Test(Integer id, String name, boolean isSomething)
	{
		this.id = id;
		this.name = name;
		this.isSomething = isSomething;
	}

	public Integer getId()
	{
		return id;
	}

	public void setId(Integer id)
	{
		this.id = id;
	}

	public String getName()
	{
		return name;
	}

	public void setName(String name)
	{
		this.name = name;
	}

	public boolean getIsSomething()
	{
		return isSomething;
	}

	public void setIsSomething(boolean isSomething)
	{
		this.isSomething = isSomething;
	}
}

EntityManager em = getEntityManager();
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery c = cb.createQuery();
Root<Test> t = c.from(Test.class);
Expression testcase = cb.selectCase()
	.when(cb.isTrue(t.get(Test_.isSomething)), cb.concat(t.get(Test_.name), " C"))
	.otherwise(t.get(Test_.name));
c.multiselect(testcase);
TypedQuery q1 = em.createQuery(c);
List result = q1.getResultList();

SELECT CASE WHEN (isSomething = ?) THEN (isSomething = ?) ELSE name END  FROM tbltest
	bind => [true, true]

        public Case<R> when(Expression<Boolean> condition, Expression<? extends R> result){
            org.eclipse.persistence.expressions.Expression conditionExp = ((InternalSelection)condition).getCurrentNode();
            conditionExp = org.eclipse.persistence.expressions.Expression.from(conditionExp, currentNode);
            ((FunctionExpression)currentNode).addChild(conditionExp);
            org.eclipse.persistence.expressions.Expression resultExp = ((InternalSelection)condition).getCurrentNode();
            resultExp = org.eclipse.persistence.expressions.Expression.from(resultExp, currentNode);
            ((FunctionExpression)currentNode).addChild(resultExp);
            return this;
        }

public Case<R> when(Expression<Boolean> condition, Expression<? extends R> result){
            org.eclipse.persistence.expressions.Expression conditionExp = ((InternalSelection)condition).getCurrentNode();
            conditionExp = org.eclipse.persistence.expressions.Expression.from(conditionExp, currentNode);
            ((FunctionExpression)currentNode).addChild(conditionExp);
            org.eclipse.persistence.expressions.Expression resultExp = org.eclipse.persistence.expressions.Expression.from(result, currentNode);
            ((FunctionExpression)currentNode).addChild(resultExp);
            return this;
        }