How to read UTF-8 encoded text file randomly?

Question

I am trying to read a text file which has been encoded in UTF-8. The problem is that I need to access the file randomly. The RandomAccessFile is a low-level class and there seems to be no-way to wrap it in InputStreamReader so that UTF-8 encoding can be done on-the-fly. Is there any easy way to do that. Below is the simplified version of my program.
import java.io.*;
public class Test{
        public Test(String filename){
                try{
                        RandomAccessFile rafTemIn = new RandomAccessFile(new File(filename), "r");
                        while(true){
                                char chr = rafTemIn.readChar();
                                System.err.println(chr);
                } catch (EOFException e) {
                        System.err.println("File read.");
                } catch (IOException e) {
                        System.err.println("File input error");
        public static void main(String[] args){
                Test t= new Test("template.idx");
}

Answer 1

The file that I am going to read could be few hundreds of MBs or GBs. Hence, I will index interesting items in the file. The index file contain the keyword and the byte offset in the file. So, I will need to seek to any byte to read it. The file could be UTF-8 encoded XML or UTF-8 encoded plain text.
Also, would like to add-up that in the sample program above I am reading the file sequentially. The concerned class has another method which actually does the reading randomly. If this helps, I am pasting the simplified version of code again but this also includes the said method.
import java.io.*;
public class Test{
        long bloc;
        long eloc;
        RandomAccessFile rafTemIn;
        public Test(String filename){
                bloc=0L;
                eloc=0L;
                try{
                        rafTemIn = new RandomAccessFile(new File(filename), "r");
                        while(true){
                                char chr = rafTemIn.readChar();
                                System.err.println(chr);
                } catch (EOFException e) {
                        System.err.println("File read.");
                } catch (IOException e) {
                        System.err.println("File input error");
        public String getVal(String templateName){
                String stemval=null;
                try {
                        rafTemIn.seek(bloc); //bloc is a long value for beginng location to read from. It changes.
                        byte[] b = new byte[(int)(eloc - bloc + 1L)];
                        rafTemIn.read(b,0,(int) (eloc - bloc + 1L));
                        stemval = new String(b,"UTF-8");
                } catch(IOException eio) {
                        System.err.println("Template Dump file IO error.");
                return stemval;
        public static void main(String[] args){
                Test t= new Test("template.idx");
                System.out.println(t.getVal("wikipedia"));
}