Develop Reference

Why opencsv capitalizing csv headers while writing to file

While writing Beans to CSV file by using OpenCSV 4.6, all the headers are changing to uppercase. Eventhough bean has #CsvBindByName annotation it is changing to uppercase.
Java Bean:
public class ProjectInfo implements Serializable {
#CsvBindByName(column = "ProjectName",required = true)
private String projectName;
#CsvBindByName(column = "ProjectCode",required = true)
private String projectCode;
#CsvBindByName(column = "Visibility",required = true)
private String visibility;
//setters and getters
}
Main method
public static void main(String[] args) throws IOException {
Collection<Serializable> projectInfos = getProjectsInfo();
try(BufferedWriter writer = new BufferedWriter(new FileWriter("test.csv"))){
StatefulBeanToCsvBuilder builder = new StatefulBeanToCsvBuilder(writer);
StatefulBeanToCsv beanWriter = builder
.withSeparator(';')
.build();
try {
beanWriter.write(projectInfos.iterator());
writer.flush();
} catch (CsvDataTypeMismatchException | CsvRequiredFieldEmptyException e) {
throw new RuntimeException("Failed to download admin file");
}
}
}
Expected Result:
"ProjectCode";"ProjectName";"Visibility"
"ANY";"Country DU";"1"
"STD";"Standard";"1"
"TST";"Test";"1"
"CMM";"CMMTest";"1"
Acutal Result:
"PROJECTCODE";"PROJECTNAME";"VISIBILITY"
"ANY";"Country DU";"1"
"STD";"Standard";"1"
"TST";"Test";"1"
"CMM";"CMMTest";"1"
I don't have option to use ColumnMappingStrategy because I have to build this method as a generic solution.
can anyone suggest me how to write the headers as it is?

It happens, because the code in HeaderColumnNameMappingStrategy uses toUpperCase() for storing and retrieving the field names.
You could use the HeaderColumnNameTranslateMappingStrategy instead and create the mapping by reflection.
public class AnnotationStrategy extends HeaderColumnNameTranslateMappingStrategy
{
public AnnotationStrategy(Class<?> clazz)
{
Map<String,String> map=new HashMap<>();
//To prevent the column sorting
List<String> originalFieldOrder=new ArrayList<>();
for(Field field:clazz.getDeclaredFields())
{
CsvBindByName annotation = field.getAnnotation(CsvBindByName.class);
if(annotation!=null)
{
map.put(annotation.column(),annotation.column());
originalFieldOrder.add(annotation.column());
}
}
setType(clazz);
setColumnMapping(map);
//Order the columns as they were created
setColumnOrderOnWrite((a,b) -> Integer.compare(originalFieldOrder.indexOf(a), originalFieldOrder.indexOf(b)));
}
#Override
public String[] generateHeader(Object bean) throws CsvRequiredFieldEmptyException
{
String[] result=super.generateHeader(bean);
for(int i=0;i<result.length;i++)
{
result[i]=getColumnName(i);
}
return result;
}
}
And, assuming that there is only one class of items (and always at least one item), the creation of beanWriter has to be expanded:
StatefulBeanToCsv beanWriter = builder.withSeparator(';')
.withMappingStrategy(new AnnotationStrategy(projectInfos.iterator().next().getClass()))
.build();

Actually, HeaderColumnNameMappingStrategy uses toUpperCase() for storing and retrieving the field names.
In order to use custom field name you have to annotate you field with #CsvBindByName
#CsvBindByName(column = "Partner Code" )
private String partnerCode;
By default it will be capitalized to PARTNER CODE because of the above reason.
so, in order to take control over it we have to write a class implementing HeaderColumnNameTranslateMappingStrategy. With csv 5.0 and java8 i have implemented like this
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;
import com.opencsv.bean.CsvBindByName;
import com.opencsv.bean.HeaderColumnNameTranslateMappingStrategy;
import com.opencsv.exceptions.CsvRequiredFieldEmptyException;
public class AnnotationStrategy<T> extends HeaderColumnNameTranslateMappingStrategy<T> {
Map<String, String> columnMap = new HashMap<>();
public AnnotationStrategy(Class<? extends T> clazz) {
for (Field field : clazz.getDeclaredFields()) {
CsvBindByName annotation = field.getAnnotation(CsvBindByName.class);
if (annotation != null) {
columnMap.put(field.getName().toUpperCase(), annotation.column());
}
}
setType(clazz);
}
#Override
public String getColumnName(int col) {
String name = headerIndex.getByPosition(col);
return name;
}
public String getColumnName1(int col) {
String name = headerIndex.getByPosition(col);
if(name != null) {
name = columnMap.get(name);
}
return name;
}
#Override
public String[] generateHeader(T bean) throws CsvRequiredFieldEmptyException {
String[] result = super.generateHeader(bean);
for (int i = 0; i < result.length; i++) {
result[i] = getColumnName1(i);
}
return result;
}
}

I have tried other solutions but it doesn't work when the property name and column name are not the same.
I am using 5.6. My solution is to reuse the strategy.
public class CsvRow {
#CsvBindByName(column = "id")
private String id;
// Property name and column name are different
#CsvBindByName(column = "country_code")
private String countryCode;
}
// We are going to reuse this strategy
HeaderColumnNameMappingStrategy<CsvRow> strategy = new HeaderColumnNameMappingStrategy<>();
strategy.setType(CsvRow.class);
// Build the header line which respects the declaration order
// So its value will be "id,country_code"
String headerLine = Arrays.stream(CsvRow.class.getDeclaredFields())
.map(field -> field.getAnnotation(CsvBindByName.class))
.filter(Objects::nonNull)
.map(CsvBindByName::column)
.collect(Collectors.joining(","));
// Let the library to initialize column details in the strategy
try (StringReader stringReader = new StringReader(headerLine);
CSVReader reader = new CSVReader(stringReader)) {
CsvToBean<CsvRow> csv = new CsvToBeanBuilder<CsvRow>(reader)
.withType(CsvRow.class)
.withMappingStrategy(strategy)
.build();
for (CsvRow csvRow : csv) {}
}
The strategy is ready for writing csv file.
try (OutputStream outputStream = Files.newOutputStream(Path.of("test.csv"));
OutputStreamWriter writer = new OutputStreamWriter(outputStream)) {
StatefulBeanToCsv<CsvRow> csv = new StatefulBeanToCsvBuilder<CsvRow>(writer)
.withMappingStrategy(strategy)
.withThrowExceptions(true)
.build();
csv.write(csvRows);
}

Using opencsv 5.0 and Java 8, I had to modify AnnotationStrategy class code as follows to had it compiled :
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;
import com.opencsv.bean.CsvBindByName;
import com.opencsv.bean.HeaderColumnNameTranslateMappingStrategy;
import com.opencsv.exceptions.CsvRequiredFieldEmptyException;
public class AnnotationStrategy<T> extends HeaderColumnNameTranslateMappingStrategy<T> {
public AnnotationStrategy(Class<? extends T> clazz) {
Map<String, String> map = new HashMap<>();
for (Field field : clazz.getDeclaredFields()) {
CsvBindByName annotation = field.getAnnotation(CsvBindByName.class);
if (annotation != null) {
map.put(annotation.column(), annotation.column());
}
}
setType(clazz);
setColumnMapping(map);
}
#Override
public String[] generateHeader(T bean) throws CsvRequiredFieldEmptyException {
String[] result = super.generateHeader(bean);
for (int i = 0; i < result.length; i++) {
result[i] = getColumnName(i);
}
return result;
}
}

Cannot construct java.util.Collection xstream

I am having troubles unmarshalling some xml using the XStream library. The related java class uses the java.util.Collection class in order to store some attributes, which I understand is a problem for XStream. However, I am unable to change the Java class to use something like ArrayList due to various reasons. Is there a way to unmarshal the xml using XStream, or should I search other libraries for a solution?
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.annotations.XStreamAlias;
import com.thoughtworks.xstream.annotations.XStreamImplicit;
import org.testng.annotations.Test;
import java.io.*;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
public class ControllerTest {
#XStreamAlias("controllers")
public class ControllerList implements Serializable {
#XStreamImplicit(
itemFieldName = "controller"
)
private List<Controller> controllers = new ArrayList();
public ControllerList() {
}
public List<Controller> getControllers() {
return this.controllers;
}
public void setControllers(List<Controller> controllers) {
this.controllers = controllers;
}
}
#XStreamAlias("controller")
public class Controller extends BasicInfo {
#XStreamImplicit(
itemFieldName = "storageInfo"
)
private Collection<BasicInfo> storage;
public Controller() {
}
public Collection<BasicInfo> getStorage() {
return this.storage;
}
public void setStorage(Collection<BasicInfo> storage) {
this.storage = storage;
}
}
#XStreamAlias("basicinfo")
public class BasicInfo{
private String name;
public BasicInfo() {
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
}
#Test(groups = {"edge"})
public void testControllers() {
String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><controllers><controller><storageInfo>" +
"<name>My name</name></storageInfo></controller></controllers>";
XStream stream = new XStream();
stream.processAnnotations(ControllerList.class);
InputStream in = new ByteArrayInputStream(xml.getBytes());
try {
InputStreamReader rdr = new InputStreamReader(in, "UTF-8");
ControllerList controllers = (ControllerList) stream.fromXML(rdr);
} catch (UnsupportedEncodingException e) {
}
}
}

XStream CollectionConverter does not supports java.util.Collection. So, you can try in two ways:
replace Collection by List:
import java.util.List;
import com.thoughtworks.xstream.annotations.XStreamAlias;
import com.thoughtworks.xstream.annotations.XStreamImplicit;
#XStreamAlias("controller")
public class Controller {
#XStreamImplicit(itemFieldName = "storageInfo")
private List<BasicInfo> storage;
public List<BasicInfo> getStorage() {
return storage;
}
public void setStorage(final List<BasicInfo> storage) {
this.storage = storage;
}
}
This test should work for the first case:
#Test
public void testControllers() {
final String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><controllers><controller><storageInfo><name>My name</name></storageInfo></controller></controllers>";
final XStream stream = new XStream();
stream.processAnnotations(ControllerList.class);
final ControllerList controllers = (ControllerList) stream.fromXML(xml);
final List<Controller> colls = controllers.getControllers();
Assert.assertEquals(colls.size(), 1);
final Controller coll = colls.get(0);
final List<BasicInfo> infos = coll.getStorage();
Assert.assertEquals(infos.size(), 1);
final BasicInfo info = infos.get(0);
Assert.assertEquals(info.getName(), "My name");
}
Add a default implementation to java.util.Collection. This test should work:
#Test
public void testControllers() {
final String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><controllers><controller><storageInfo><name>My name</name></storageInfo></controller></controllers>";
final XStream stream = new XStream();
stream.processAnnotations(ControllerList.class);
stream.addDefaultImplementation(ArrayList.class, Collection.class);
final ControllerList controllers = (ControllerList) stream.fromXML(xml);
final List<Controller> colls = controllers.getControllers();
Assert.assertEquals(colls.size(), 1);
final Controller coll = colls.get(0);
final Collection<BasicInfo> infos = coll.getStorage();
Assert.assertEquals(infos.size(), 1);
for (final BasicInfo info : infos) {
Assert.assertEquals(info.getName(), "My name");
}
}

How to list all properties exposed by a Java class and its ancestors in Eclipse?

Given a single Java class I'd like to be able to list all properties that are exposed in all ancestors and recursively traverse all their exposed properties (i.e. public or with getters/setters) in the same way.
Easier to explain with a simple example:
public class BaseClass1 {
private int intProperty; // has getter and setter (not shown)
}
public class SubClass1 extends BaseClass1 {
private int privateSoNotListed;
public SubClass2 subClass2Property;
}
public class BaseClass2 {
public String stringProperty;
}
public class SubClass2 extends BaseClass2 {
private long longProperty; // has getter and setter (not shown)
}
Given SubClass1 above as input, the output would be something like this:
intProperty - int [from BaseClass1]
subClass2Property.stringProperty - String [from BaseClass2]
subClass2Property.longProperty - long [from SubClass2]
It should be possible to write something like this using a bit of clever reflection but I'd rather not reinvent the wheel - is there an existing tool that can do this (perhaps an Eclipse plugin?)
EDIT: Eclipse's Type Hierarchy does a nice job of displaying properties for a single class - the ideal solution in my mind would be if this were a tree view (similar to Package Explorer) with the ability to expand properties that are themselves classes.

See also the duplicate Recursive BeanUtils.describe(), which works also recursively. The following is a custom version we are using (logs in a log4j logger):
import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import org.apache.commons.beanutils.BeanUtilsBean;
import org.apache.commons.beanutils.ConvertUtilsBean;
import org.apache.log4j.Logger;
/*
* See the original version: https://stackoverflow.com/questions/6133660/recursive-beanutils-describe
*/
public class Inspector {
public static void recursivelyDescribeAndLog(Object ob, Logger log){
log.info(ob.getClass());
try {
Map<String, String> props = recursiveDescribe(ob);
for (Map.Entry<String, String> p : props.entrySet()) {
log.info(" -> " + p.getKey() + "="+p.getValue());
}
} catch (Throwable e) {
log.error(e.getMessage(), e);
}
}
public static Map<String, String> recursiveDescribe(Object object) {
Set cache = new HashSet();
return recursiveDescribe(object, null, cache);
}
private static Map<String, String> recursiveDescribe(Object object, String prefix, Set cache) {
if (object == null || cache.contains(object)) return Collections.EMPTY_MAP;
cache.add(object);
prefix = (prefix != null) ? prefix + "." : "";
Map<String, String> beanMap = new TreeMap<String, String>();
Map<String, Object> properties = getProperties(object);
for (String property : properties.keySet()) {
Object value = properties.get(property);
try {
if (value == null) {
//ignore nulls
} else if (Collection.class.isAssignableFrom(value.getClass())) {
beanMap.putAll(convertAll((Collection) value, prefix + property, cache));
} else if (value.getClass().isArray()) {
beanMap.putAll(convertAll(Arrays.asList((Object[]) value), prefix + property, cache));
} else if (Map.class.isAssignableFrom(value.getClass())) {
beanMap.putAll(convertMap((Map) value, prefix + property, cache));
} else {
beanMap.putAll(convertObject(value, prefix + property, cache));
}
} catch (Exception e) {
e.printStackTrace();
}
}
return beanMap;
}
private static Map<String, Object> getProperties(Object object) {
Map<String, Object> propertyMap = getFields(object);
//getters take precedence in case of any name collisions
propertyMap.putAll(getGetterMethods(object));
return propertyMap;
}
private static Map<String, Object> getGetterMethods(Object object) {
Map<String, Object> result = new HashMap<String, Object>();
BeanInfo info;
try {
info = Introspector.getBeanInfo(object.getClass());
for (PropertyDescriptor pd : info.getPropertyDescriptors()) {
Method reader = pd.getReadMethod();
if (reader != null) {
String name = pd.getName();
if (!"class".equals(name)) {
try {
Object value = reader.invoke(object);
result.put(name, value);
} catch (Exception e) {
//you can choose to do something here
}
}
}
}
} catch (IntrospectionException e) {
//you can choose to do something here
} finally {
return result;
}
}
private static Map<String, Object> getFields(Object object) {
return getFields(object, object.getClass());
}
private static Map<String, Object> getFields(Object object, Class<?> classType) {
Map<String, Object> result = new HashMap<String, Object>();
Class superClass = classType.getSuperclass();
if (superClass != null) result.putAll(getFields(object, superClass));
//get public fields only
Field[] fields = classType.getFields();
for (Field field : fields) {
try {
result.put(field.getName(), field.get(object));
} catch (IllegalAccessException e) {
//you can choose to do something here
}
}
return result;
}
private static Map<String, String> convertAll(Collection<Object> values, String key, Set cache) {
Map<String, String> valuesMap = new HashMap<String, String>();
Object[] valArray = values.toArray();
for (int i = 0; i < valArray.length; i++) {
Object value = valArray[i];
if (value != null) valuesMap.putAll(convertObject(value, key + "[" + i + "]", cache));
}
return valuesMap;
}
private static Map<String, String> convertMap(Map<Object, Object> values, String key, Set cache) {
Map<String, String> valuesMap = new HashMap<String, String>();
for (Object thisKey : values.keySet()) {
Object value = values.get(thisKey);
if (value != null) valuesMap.putAll(convertObject(value, key + "[" + thisKey + "]", cache));
}
return valuesMap;
}
private static ConvertUtilsBean converter = BeanUtilsBean.getInstance().getConvertUtils();
private static Map<String, String> convertObject(Object value, String key, Set cache) {
//if this type has a registered converted, then get the string and return
if (converter.lookup(value.getClass()) != null) {
String stringValue = converter.convert(value);
Map<String, String> valueMap = new HashMap<String, String>();
valueMap.put(key, stringValue);
return valueMap;
} else {
//otherwise, treat it as a nested bean that needs to be described itself
return recursiveDescribe(value, key, cache);
}
}
}

have a look at apache commons beanutils. they have utility classes that will allow you to list properties (among other things) - specifically PropertyUtilsBean.getPropertyDescriptors().
note that their definiteion of a "property" is something that is accessible/editable via getter/setter methods. if you want to list fields you'd need to do something else

Have just found a useful way of achieving something fairly similar to what was originally asked via Eclipse's Type Hierarchy.
There is a toggle named "Show All Inherited Members" as shown by the red arrow below:
After selecting this, the fields and methods from all superclasses are displayed in addition to those for the selected class (with a clear indication of where each one came from), as shown below:
(Of course, this includes more than just properties but since the getters are displayed in alphabetical order and there are icons for public/private/protected, it can be used to obtain this information easily enough.)

How can I get Gson to use accessors rather than fields?

By default Gson uses fields as a basis for it's serialization. Is there a way to get it to use accessors instead?

The developers of Gson say that they never felt swayed by the requests to add this feature and they were worried about murkying up the api to add support for this.
One way of adding this functionality is by using a TypeAdapter (I apologize for the gnarly code but this demonstrates the principle):
import java.io.IOException;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import com.google.common.base.CaseFormat;
import com.google.gson.Gson;
import com.google.gson.TypeAdapter;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
public class AccessorBasedTypeAdaptor<T> extends TypeAdapter<T> {
private Gson gson;
public AccessorBasedTypeAdaptor(Gson gson) {
this.gson = gson;
}
#SuppressWarnings("unchecked")
#Override
public void write(JsonWriter out, T value) throws IOException {
out.beginObject();
for (Method method : value.getClass().getMethods()) {
boolean nonBooleanAccessor = method.getName().startsWith("get");
boolean booleanAccessor = method.getName().startsWith("is");
if ((nonBooleanAccessor || booleanAccessor) && !method.getName().equals("getClass") && method.getParameterTypes().length == 0) {
try {
String name = method.getName().substring(nonBooleanAccessor ? 3 : 2);
name = CaseFormat.UPPER_CAMEL.to(CaseFormat.LOWER_CAMEL, name);
Object returnValue = method.invoke(value);
if(returnValue != null) {
TypeToken<?> token = TypeToken.get(returnValue.getClass());
TypeAdapter adapter = gson.getAdapter(token);
out.name(name);
adapter.write(out, returnValue);
}
} catch (Exception e) {
throw new ConfigurationException("problem writing json: ", e);
}
}
}
out.endObject();
}
#Override
public T read(JsonReader in) throws IOException {
throw new UnsupportedOperationException("Only supports writes.");
}
}
You can register this as a normal type adapter for a given type or through a TypeAdapterfactory - possibly checking for the presence of a runtime annotation:
public class TypeFactory implements TypeAdapterFactory {
#SuppressWarnings("unchecked")
public <T> TypeAdapter<T> create(final Gson gson, final TypeToken<T> type) {
Class<? super T> t = type.getRawType();
if(t.isAnnotationPresent(UseAccessor.class)) {
return (TypeAdapter<T>) new AccessorBasedTypeAdaptor(gson);
}
return null;
}
This can be specified as normal when creating your gson instance:
new GsonBuilder().registerTypeAdapterFactory(new TypeFactory()).create();

Note: I'm the EclipseLink JAXB (MOXy) lead and a member of the JAXB (JSR-222) expert group.
If you can't get Gson to do what you want, below is how you can accomplish this using MOXy's native JSON binding. MOXy like any JAXB implementation will use property (public) access by default. You can configure field access using #XmlAccessorType(XmlAccessType.FIELD). Below is an example:
Customer
package forum11385214;
public class Customer {
private String foo;
private Address bar;
public String getName() {
return foo;
}
public void setName(String name) {
this.foo = name;
}
public Address getAddress() {
return bar;
}
public void setAddress(Address address) {
this.bar = address;
}
}
Address
package forum11385214;
public class Address {
private String foo;
public String getStreet() {
return foo;
}
public void setStreet(String street) {
this.foo = street;
}
}
jaxb.properties
To configure MOXy as your JAXB provider you need to add a file called jaxb.properties in the same package as your domain model with the following entry (see: http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html).
javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory
Demo
package forum11385214;
import java.util.*;
import javax.xml.bind.*;
import javax.xml.transform.stream.StreamSource;
import org.eclipse.persistence.jaxb.JAXBContextProperties;
public class Demo {
public static void main(String[] args) throws Exception {
Map<String, Object> properties = new HashMap<String, Object>(2);
properties.put(JAXBContextProperties.MEDIA_TYPE, "application/json");
properties.put(JAXBContextProperties.JSON_INCLUDE_ROOT, false);
JAXBContext jc = JAXBContext.newInstance(new Class[] {Customer.class}, properties);
Unmarshaller unmarshaller = jc.createUnmarshaller();
StreamSource json = new StreamSource("src/forum11385214/input.json");
Customer customer = (Customer) unmarshaller.unmarshal(json, Customer.class).getValue();
Marshaller marshaller = jc.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(customer, System.out);
}
}
input.json/Output
{
"name" : "Jane Doe",
"address" : {
"street" : "1 Any Street"
}
}
For More Information
http://blog.bdoughan.com/2011/08/json-binding-with-eclipselink-moxy.html
http://blog.bdoughan.com/2011/06/using-jaxbs-xmlaccessortype-to.html
http://blog.bdoughan.com/2012/04/jaxb-and-unmapped-properties.html

JAXB Java generating XML, Why lowercase?

When I run this code:
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlRootElement;
public class JavaToXMLDemo {
public static void main(String[] args) throws Exception {
JAXBContext context = JAXBContext.newInstance(Employee.class);
Marshaller m = context.createMarshaller();
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
Employee object = new Employee();
object.setCode("CA");
object.setName("Cath");
object.setSalary(300);
m.marshal(object, System.out);
}
}
#XmlRootElement
#XmlAccessorType(XmlAccessType.FIELD)
class Employee {
private String code;
private String name;
private int salary;
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getSalary() {
return salary;
}
public void setSalary(int population) {
this.salary = population;
}
}
I get
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<employee>
<code>CA</code>
<name>Cath</name>
<salary>300</salary>
</employee>
Which is correct, so my question is why does it change the Employee to employee?
Is it possible to make it print with uppercase E, instead of employee?
This is what I actually wanted to have:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Employee>
<code>CA</code>
<name>Cath</name>
<salary>300</salary>
</Employee>
Thanks!

The behaviour you are seeing is the result of the standard JAXB (JSR-222) XML name to Java name conversion algorithm.
You can use the #XmlRootElement annotation to specify a name:
#XmlRootElement(name="Employee")
#XmlAccessorType(XmlAccessType.FIELD)
class Employee {
...
}
I'm the EclipseLink JAXB (MOXy) lead, and we have an extension that allows you to override the default name conversion algorithm that you may be interested in:
http://blog.bdoughan.com/2011/05/overriding-jaxbs-name-mangling.html

For specific elements...
#XmlElement( name = "Code")
private String code;
For the object....
#XmlRootElement(name="Employee")
public class Employee{ ...

My solution after put #XmlElement(name="Xxxxx") to fields and used XStream.aliasField(). This is more generic because it uses annotations and scans other class calls in the same package.
import java.lang.reflect.Field;
import java.util.Map;
import java.util.TreeMap;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlAttribute;
import com.thoughtworks.xstream.XStream;
import my.MyClassGeneratedFromXsdToJaxB;
public class TestChangeFirstLetterXml {
public static void main(String[] args) throws ClassNotFoundException {
MyClassGeneratedFromXsdToJaxB myClassGeneratedFromXsdToJaxB=new MyClassGeneratedFromXsdToJaxB();
XStream xstream = new XStream();
xstream.autodetectAnnotations(true);
xstream = makeAliasAnnotatedFields(xstream, MyClassGeneratedFromXsdToJaxB.class, "FirstTagOrRoot");
//System.out.println(xstream.toXML(myClassGeneratedFromXsdToJaxB));
}
public static XStream makeAliasAnnotatedFields(XStream xstream, Class myclass, String firstTag)
throws ClassNotFoundException {
xstream.alias(firstTag, myclass);
Map<String, Object[]> aliaslist = getListAlias(myclass);
for (String key : aliaslist.keySet()) {
Object[] aliasvalue = new Object[3];
aliasvalue = aliaslist.get(key);
String xmlTag = new String((String) aliasvalue[0]);
Class<?> classJaxb = (Class<?>) aliasvalue[1];
String tagToRename = new String((String) aliasvalue[2]);
xstream.aliasField(xmlTag, classJaxb, tagToRename);
System.out.println("AliasField " + xmlTag + " " + classJaxb.getName() + " " + tagToRename);
}
return xstream;
}
public static Map<String, Object[]> getListAlias(Class<?> classToCheck)
throws ClassNotFoundException {
/* Read recursive fields of the class */
Field[] fs = classToCheck.getDeclaredFields();
String annotationsPackage = classToCheck.getPackage().getName();
String classSimpleName = new String(classToCheck.getSimpleName());
/* it is necessary avoid loop */
Map<String, Object[]> aliasStart = new TreeMap<String, Object[]>();
/* */
for (int i = 0; i < fs.length; i++) {
String nameField = fs[i].getName();
String classFieldName = new String(fs[i].getType().getName());
String nameXmlXsd = new String("");
String idkey = new String(annotationsPackage + ".");
if (fs[i].isAnnotationPresent(javax.xml.bind.annotation.XmlElement.class)) {
XmlElement atrib = fs[i].getAnnotation(XmlElement.class);
nameXmlXsd = new String(atrib.name());
idkey = new String(idkey + classSimpleName + ".Element." + nameField);
} else if (fs[i].isAnnotationPresent(javax.xml.bind.annotation.XmlAttribute.class)) {
XmlAttribute atrib = fs[i].getAnnotation(XmlAttribute.class);
nameXmlXsd = new String(atrib.name());
idkey = new String(idkey + classSimpleName + ".Type." + nameField);
}
if (aliasStart.containsKey(idkey)) /* avoid loop */
continue;
if (nameXmlXsd.equals("Signature")) // My particular condition
continue;
if (!nameXmlXsd.equals(classFieldName)) {
// xstrem.aliasField(a,b,c)
Object[] alias = new Object[3];
alias[0] = new String(nameXmlXsd);
alias[1] = classToCheck;
alias[2] = new String(nameField);
aliasStart.put(idkey, alias);
}
if (classFieldName.indexOf(annotationsPackage) > -1) {
Class<?> c = Class.forName(classFieldName);
Map<String, Object[]> aliaslist = getListAlias(c);
for (String key : aliaslist.keySet()) {
Object[] aliasvalue = new Object[3];
aliasvalue = aliaslist.get(key);
aliasStart.put(key, aliasvalue);
}
}
}
return aliasStart;
}
}

An alternative answer, if JAXB is not a MUST, then you can actually use org.json jar to convert the object to a JSONObject, then from there, you can use the XML object to convert the JSONObject to an XML. You will need a few tweaks before it can be a standalone XML.
A code snippet example:
public static String getXMLString(Object o){
JSONObject json = new JSONObject(o);
String result =
"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>" +
XML.toString(json, o.getClass().getSimpleName());
return result;
}