FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
On this page it lists -XX:+UseCompressedStrings as on by default.

http://www.oracle.com/technetwork/java/javase/tech/vmoptions-jsp-140102.html

 However in Java 6 update 29 its off by default and in Java 7 update 2 it reports

Java HotSpot(TM) 64-Bit Server VM warning: ignoring option UseCompressedStrings; support was removed in 7.0

The program below requires a heap of 2000m on Java 7, 1800m on Java 6 without compressed Strings and 1000m with compressed Strings. Its also faster with compressed Strings turned on.

REGRESSION. Last worked in version 7

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Try Java 6 and 7 with and without UseCompressedStrings

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Options to improve performance to retained

OR

The documentation to reflect which options are available. A note as to why its not available would be very interesting.
ACTUAL -
Neither

ERROR MESSAGES/STACK TRACES THAT OCCUR :
OutOfMemoryError if you don't have 2 GB for the heap.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.io.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class Main {
    public static void main(String... args) throws IOException {
        long start = System.nanoTime();
        generateFile("lines.txt", 755 * 1024 * 1024, 189000);

        List<String> lines = loadLines("lines.txt");

        System.out.println("Sorting file");
        Collections.sort(lines);
        System.out.println("... Sorted file");
        // save lines.
        long time = System.nanoTime() - start;
        System.out.printf("Took %.3f second to read, sort and write to a file%n", time / 1e9);
    }

    private static void generateFile(String fileName, int size, int lines) throws FileNotFoundException {
        System.out.println("Creating file to load");
        int lineSize = size / lines;
        StringBuilder sb = new StringBuilder();
        while (sb.length() < lineSize) sb.append('-');
        String padding = sb.toString();

        PrintWriter pw = new PrintWriter(fileName);
        for (int i = 0; i < lines; i++) {
            String text = (i + padding).substring(0, lineSize);
            pw.println(text);
        }
        pw.close();
        System.out.println("... Created file to load");
    }

    private static List<String> loadLines(String fileName) throws IOException {
        System.out.println("Reading file");
        BufferedReader br = new BufferedReader(new FileReader(fileName));
        List<String> ret = new ArrayList<String>();
        String line;
        while ((line = br.readLine()) != null)
            ret.add(line);
        System.out.println("... Read file.");
        return ret;
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Use older version of Java until fixed.

SUPPORT :
YES