Deserializing on Ukrain Pc

I'm using the following code to serialize objects
private static Gson newInstance() {
return new GsonBuilder()
.serializeNulls()
.setDateFormat(DATETIME_FORMAT)
.excludeFieldsWithoutExposeAnnotation()
.create();
}

```
public static String objectToJson(Object obj) {
return newInstance().toJson(obj);
}

public static T jsonToObject(String json, Class objClass) {
return newInstance().fromJson(json, objClass);
}
```

THIS works perfect on my windows PC to decerialise the following string into object

String : {"params":[{"join":"and","field":"medName","operator":"like","value":"ADA%"}]}
Class :
public class HibParams {

```
@Expose
List params;

class Param {

@Expose
String join;
@Expose
String field;
@Expose
String operator;
@Expose
String value;

public Param(String join, String field, String operator, String value) {
this.join = join;
this.field = field;
this.operator = operator;
this.value = value;
}

}

public HibParams() {
params = new ArrayList();
}

public void addAnd(String field, String operator, String value) {
Param p = new Param("and", field, operator, value);
this.params.add(p);
}

public void addOr(String field, String operator, String value) {
Param p = new Param("or", field, operator, value);
this.params.add(p);
}
```

}

However on an PC with Ukrain characterset this always retrun a null object.

Help would be appreiated