Name: tb29552 Date: 08/18/97


company - Electric Communities , email - ###@###.###

Here is the source code for my test and the results. Please let
me know if you need additional help.

public class TestIntern {

static public void main(String[] args) throws Throwable {

String s = "TestMessage";

try {
for (;;) {
     int i = s.length()/2;
                if (i > 250000) {
             i = s.length()-1;
                }
     s = s+s.substring(i);
     s = s.intern();
            System.out.println("String length " + s.length()+", i="+i);
     }
} catch(OutOfMemoryError e) {
System.err.println("String length is " + s.length());
     e.printStackTrace();
}
}
}

Here's the result:

groucho% java TestIntern
String length 17, i=5
String length 26, i=8
String length 39, i=13
String length 59, i=19
String length 89, i=29
String length 134, i=44
String length 201, i=67
String length 302, i=100
String length 453, i=151
String length 680, i=226
String length 1020, i=340
String length 1530, i=510
String length 2295, i=765
String length 3443, i=1147
String length 5165, i=1721
String length 7748, i=2582
String length 11622, i=3874
String length 17433, i=5811
String length 26150, i=8716
String length 39225, i=13075
String length 58838, i=19612
String length 88257, i=29419
String length 132386, i=44128
String length 198579, i=66193
String length 297869, i=99289
String length 446804, i=148934
String length 670206, i=223402
String length 670207, i=670205
String length 670208, i=670206
String length 670209, i=670207
String length 670210, i=670208
String length is 670210
java.lang.OutOfMemoryError
        at java.lang.StringBuffer.<init>(StringBuffer.java)
        at java.lang.StringBuffer.<init>(StringBuffer.java)
        at TestIntern.main(TestIntern.java:15)

If I comment out the s.intern() call, I get:

... deleted output lines
String length 297869, i=99289
String length 446804, i=148934
String length 670206, i=223402
String length 670207, i=670205
String length 670208, i=670206
String length 670209, i=670207
String length 670210, i=670208
String length 670211, i=670209
String length 670212, i=670210
String length 670213, i=670211
String length 670214, i=670212
String length 670215, i=670213
String length 670216, i=670214
String length 670217, i=670215
String length 670218, i=670216
String length 670219, i=670217
String length 670220, i=670218
String length 670221, i=670219
String length 670222, i=670220
String length 670223, i=670221
String length 670224, i=670222
String length 670225, i=670223
String length 670226, i=670224
String length 670227, i=670225
String length 670228, i=670226

Which I stopped with Control-C. My conclusion is that
interning a string protects it from ever being garbage
collected. Boo! Hiss!


company - Electric Communities , email - ###@###.###
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