**UPD:** [user:arti,2015-06-21] commented that they will be using Oracle JDK. Thanks!↵
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I maintain a online judge which uses the CMS isolate sandbox. I was trying to support Java so I looked at CMS itself, and found that they are using `gcj` (GNU Compiler for Java) as you can see in this commit.↵
↵
https://github.com/cms-dev/cms/commit/cf949952424677e0b0762eec5e461e33f85eecb3↵
↵
Of course this doesn't mean they will definitely use `gcj` and we should wait for their announcement. Disclaimer: I am not a IOI participant nor use Java in competitive programming. But I don't think they will support OpenJDK/Oracle as I (almost always) get memory allocation error when running JVM within isolate sandbox.↵
↵
`gcj` is the default java installation in Ubuntu. So far I faced two bugs. (These bugs are related to I/O and since IOI uses interface file so it may not be a problem.)↵
↵
1) Formatted floating point numbers will become empty↵
↵
~~~~~↵
public class Task {↵
public static void main(String[] args) {↵
System.out.format("$%.3f\n", 0.9876);↵
}↵
}↵
~~~~~↵
↵
~~~~~↵
Expected output: $0.988↵
Program output: $↵
~~~~~↵
↵
2) Scanner class does not work with `Scanner.in.read()`. Even if you are trying to scan integers only, you have to press enter several times. This does not happen when you use file redirection.↵
↵
~~~~~↵
import java.util.*;↵
import java.io.*;↵
public class Task {↵
public static void main(String[] args) throws IOException {↵
Scanner in = new Scanner(System.in);↵
System.out.print((char) System.in.read());↵
System.out.println(in.nextInt());↵
}↵
}↵
~~~~~↵
↵
~~~~~↵
Input: A5↵
Expected Output: A5↵
Program: ↵
(strange character)Exception in thread "main" java.util.InputMismatchException: "A5" is not an integer↵
at java.util.Scanner.myNextInt(libgcj.so.15)↵
at java.util.Scanner.nextInt(libgcj.so.15)↵
at java.util.Scanner.nextInt(libgcj.so.15)↵
at Task.main(Task.java)↵
~~~~~↵
↵
I maintain a online judge which uses the CMS isolate sandbox. I was trying to support Java so I looked at CMS itself, and found that they are using `gcj` (GNU Compiler for Java) as you can see in this commit.↵
↵
https://github.com/cms-dev/cms/commit/cf949952424677e0b0762eec5e461e33f85eecb3↵
↵
Of course this doesn't mean they will definitely use `gcj` and we should wait for their announcement. Disclaimer: I am not a IOI participant nor use Java in competitive programming. But I don't think they will support OpenJDK/Oracle as I (almost always) get memory allocation error when running JVM within isolate sandbox.↵
↵
`gcj` is the default java installation in Ubuntu. So far I faced two bugs. (These bugs are related to I/O and since IOI uses interface file so it may not be a problem.)↵
↵
1) Formatted floating point numbers will become empty↵
↵
~~~~~↵
public class Task {↵
public static void main(String[] args) {↵
System.out.format("$%.3f\n", 0.9876);↵
}↵
}↵
~~~~~↵
↵
~~~~~↵
Expected output: $0.988↵
Program output: $↵
~~~~~↵
↵
2) Scanner class does not work with `Scanner.in.read()`. Even if you are trying to scan integers only, you have to press enter several times. This does not happen when you use file redirection.↵
↵
~~~~~↵
import java.util.*;↵
import java.io.*;↵
public class Task {↵
public static void main(String[] args) throws IOException {↵
Scanner in = new Scanner(System.in);↵
System.out.print((char) System.in.read());↵
System.out.println(in.nextInt());↵
}↵
}↵
~~~~~↵
↵
~~~~~↵
Input: A5↵
Expected Output: A5↵
Program: ↵
(strange character)Exception in thread "main" java.util.InputMismatchException: "A5" is not an integer↵
at java.util.Scanner.myNextInt(libgcj.so.15)↵
at java.util.Scanner.nextInt(libgcj.so.15)↵
at java.util.Scanner.nextInt(libgcj.so.15)↵
at Task.main(Task.java)↵
~~~~~↵
