KiT106

// Bad
if (data.selected == true){
  // do staff
}
if (data.selected != true){
  // do staff
}

// Good
if ( data ) {

KiT106

// Bad
if (foo !== undefined && foo != null && foo != '') {
  // do something...
}

// Good
if (foo) {
  // do something...
}
// will evaluate to true if value is not:

KiT106

// Bad
public Employee getSingleEmployee(params...){
	String sql = ...;

	TypedQuery<Employee> query = entityManager.createQuery(sql, Employee.class);
	query.setParameter(...);

	List<Employee> list = query.getResultList();  // can load more than one result
	if (list == null || list.isEmpty()) {
    return null;

KiT106

// Bad
public List<Employee> getEmployeesByManager(Employee manager){
  String sql = "SELECT e FROM Employee e WHERE e.manager = :manager";
  Query query = entityManager.createQuery(sql);
  query.setParameter(...);
  return query.getResultList();  // Warning "unchecked"
}

// Good
TypedQuery<Employee> query = entityManager.createQuery(sql, Employee.class);

KiT106

// Bad
public static final int MARITAL_SINGLE = 1;
public static final int MARITAL_MARRIED = 2;
public static final int MARITAL_DISVORCED = 3;
public static final int MARITAL_WIDOW = 4;

public static final String MARITAL_SINGLE_NAME = "Single";
public static final String MARITAL_MARRIED_NAME = "Married";
public static final String MARITAL_DISVORCED_NAME = "Disvorced";
public static final String MARITAL_WIDOW_NAME = "Widow[er]";