Beanshell Script to generate sequence of strings

Can any one help in creating sequence of strings in multiple lines in a file using Beanshell Script

For example: Looking for output of

Test1,Test2,Test3
Test4,Test5,Test6
Test7,Test8,Test9

Tried this but giving incorrect result

int numSets = 1;    
for (int j = 1; j < numSets; j++) { 
    for (int i = 1; i <= numStrings; i++) {
    String str = "test" + i;
    if (i < numStrings) {
        result += str + ",";
    } else {
        result += str;
    }       
        out.write(str);

}
out.write("\n");
}
out.close();

Be informed that since JMeter 3.1 you should be using JSR223 Test Elements and Groovy language for scripting.

Here is an example solution in Groovy:

def lines = 3
def itemsPerLine = 3
def prefix = 'Test'
def counter = 1

1.upto(lines, { lineNumber ->
    1.upto(itemsPerLine, { itemNumber ->
        print(prefix + counter)
        if (itemNumber < itemsPerLine) {
            print(',')
        }
        counter++
    })
    print(System.getProperty('line.separator'))

})

More information: Beanshell vs. JSR223 vs. Java For JMeter: Complete Showdown

If you want to print it to jmeter.log file or to another file you can use StringBuilder.append() instead of print()