These are the tasks that users were asked to complete in the web based study.
The code that users were meant to write is put inside triple <<< >>>'s.

-------------------------------------------------------------
Task 1:

// convert "1 2 3 4" --> "1,2,3,4"
public String spacesToCommas(String message) {
    String space = " ";
    String comma = ",";
    return <<<message.replaceAll(space, comma)>>>;
} 

-------------------------------------------------------------
Task 2:

// convert "100" --> 100
String input = "100";
int output = <<<new Integer(input)>>>;

-------------------------------------------------------------
Task 3:

// make sure that the list has no more than the
// given number of elements
public void trimSize(List list, int noMoreThan) {
    while (list.size() > noMoreThan) {
        list.remove(<<<list.length() - 1>>>);
    }
}

-------------------------------------------------------------
Task 4:

public boolean isFruit(String food) {
    Set<String> fruits = 
    new HashSet<String>(getFruitList());
    return <<<fruits.contains(food)>>>;
}

-------------------------------------------------------------
Task 5:

public boolean isVowel(char c) {
    String vowels = "aeiou";
    return -1 != <<<vowels.indexOf(c)>>>;
}

-------------------------------------------------------------
Task 6:

Map<Integer, String> numberNames = new HashMap<Integer, String>();
Integer key = 3;
String value = "Three";
// make numberNames have the entry:
// 3 --> "Three"
<<<numberNames.put(key, value)>>>;

-------------------------------------------------------------
Task 7:

public int absoluteValue(int x) {
    // use standard java method to
    // return the absolute value of x
    return <<<Math.abs(x)>>>;
}

-------------------------------------------------------------
Task 8:

public Vector<String> getTokens(String message) {
    Vector<String> tokens = new Vector<String>();
    StringTokenizer st = 
    new StringTokenizer(message, " ");
    while (st.hasMoreTokens()) {
        <<<tokens.add(st.nextToken())>>>;
    }
    return tokens
}

-------------------------------------------------------------
Task 9:

// count the a's
String message = "how many a's are in this message?";
int count = 0;
for (int i = 0; i < message.length(); i++) {
    char c = <<<message.charAt(i)>>>;
    if (c == 'a') {
        count++;
    }
}

-------------------------------------------------------------
Task 10:

// example output:
// autoexec.bat
// config.sys
// Documents and Settings
// Windows
public void ls(File dir) {
    for (File f : dir.listFiles()) {
        <<<System.out.println(f.getName())>>>;
    }
}

-------------------------------------------------------------
Task 11:

public String repeatString(String s, int thisManyTimes) {
    StringBuffer buf = new StringBuffer();
    for (int i = 0; i < thisManyTimes; i++) {
        <<<buf.append(s)>>>;
    }
    return buf.toString();
}

-------------------------------------------------------------
Task 12:

public List<String> getLines(BufferedReader in) {
    List<String> lines = new Vector<String>();
    while (in.ready()) {
        <<<lines.add(in.readLine())>>>;
    }
    return lines;
}

-------------------------------------------------------------
Task 13:

public void logMessage(String message) {
    PrintWriter log = new PrintWriter(
    new FileWriter("log.txt", true));
    <<<log.println(message)>>>;
    log.close();
}

-------------------------------------------------------------
Task 14:

// convert "HeLLo WoRlD" --> "hello world"
String input = "HeLLo WoRlD";
String output = <<<input.toLowerCase()>>>;

-------------------------------------------------------------
Task 15:

String filename = "input.txt";
BufferedReader in = <<<new BufferedReader(new FileReader(filename))>>>;
in.read(...);
in.close();