what is static setter and getter examples in java

public class DataHolder
{
   private static String dataString;

   public static String getDataString
   {
      return dataString;
   }

   public static void setString(String dataString)
   {
      this.dataString = dataString;
   }
}class SomeClass {
    private static Data data;

    public static void setData(String data) {
        data = new Data(data);
    }

    public static String getData() {
        return data.toString();
    }
}

class Data {
    private String data;

    public Data(String data) {
        this.data = data;
    }

    public String toString() {
        return data;
    }
}public class DataHolder{
  private static String dataString;
  public static String getDataString(){
    synchronized(DataHolder.class){
      return DataHolder.dataString;
    }
  }

  public static void setString(String dataString){
    synchronized(DataHolder.class){
      DataHolder.dataString = dataString;
    }
  }
}public class DataHolder
{
   public static String dataString;
}