Using Java 7u5, with the try-with-resources construct, the following code appears to leak jdbc connections:
try (Connection connection = ..; PreparedStatement stmt = ..) {
stmt.setString(..);
return stmt.executeUpdate() > 0;
}
The next piece of code works as expected and intended:
int ret = 0;
try (Connection connection = ..; PreparedStatement stmt = ..) {
stmt.setString(..);
ret = stmt.executeUpdate();
}
return ret > 0;
It seems that in the first case, the Connection.close()
method is not being invoked.
I am using the latest mysql connector. This is unexpected behavior, correct?
The following test will NOT print CLOSED
:
public class Test implements AutoCloseable {
public static void main(String[] args) throws Exception {
System.out.println(doTest());
}
private static boolean doTest() throws Exception {
try (Test test = new Test()) {
return test.execute() > 0;
}
}
private int execute() {
return 1;
}
@Override
public void close() throws Exception {
System.out.println("CLOSED");
}
}
Strangely, if execute()
is modified to return 0;
then CLOSED
WILL be printed.
Compiled from "Test.java"
public class Test implements java.lang.AutoCloseable {
public Test();
Code:
0: aload_0
1: invokespecial #10 // Method java/lang/Object."<init>":()V
4: return
public static void main(java.lang.String[]) throws java.lang.Exception;
Code:
0: getstatic #21 // Field java/lang/System.out:Ljava/io/PrintStream;
3: invokestatic #27 // Method doTest:()Z
6: invokevirtual #31 // Method java/io/PrintStream.println:(Z)V
9: return
private static boolean doTest() throws java.lang.Exception;
Code:
0: aconst_null
1: astore_0
2: aconst_null
3: astore_1
4: new #1 // class Test
7: dup
8: invokespecial #39 // Method "<init>":()V
11: astore_2
12: aload_2
13: invokespecial #40 // Method execute:()I
16: ifle 21
19: iconst_1
20: ireturn
21: iconst_0
22: aload_2
23: ifnull 30
26: aload_2
27: invokevirtual #44 // Method close:()V
30: ireturn
31: astore_0
32: aload_2
33: ifnull 40
36: aload_2
37: invokevirtual #44 // Method close:()V
40: aload_0
41: athrow
42: astore_1
43: aload_0
44: ifnonnull 52
47: aload_1
48: astore_0
49: goto 62
52: aload_0
53: aload_1
54: if_acmpeq 62
57: aload_0
58: aload_1
59: invokevirtual #47 // Method java/lang/Throwable.addSuppressed:(Ljava/lang/Throwable;)V
62: aload_0
63: athrow
Exception table:
from to target type
12 22 31 any
30 31 31 any
4 42 42 any
private int execute();
Code:
0: iconst_1
1: ireturn
public void close() throws java.lang.Exception;
Code:
0: getstatic #21 // Field java/lang/System.out:Ljava/io/PrintStream;
3: ldc #55 // String CLOSED
5: invokevirtual #57 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
8: return
}
After upgrading to the latest version of eclipse (Juno), this strange behavior is no longer occurring.
It also works fine using the command line to compile and run.
I suspect Eclipse Indigo was using an old javac
to compile, and not complaining about any compliance violation.
I've encountered the very same issue using JDK 1.7.0_17. After careful elimination, it turned out it my IntelliJ was using an AspectJ compiler. Once I compiled the class explicitly with the JDK's javac it worked as expected.
My colleague has filed a bug report to the AspectJ people. They have scheduled a fix for version 1.7.3
It is a java 7u5 bug; go register a bug. Java 7u4 worked.
return test.execute() > 0;
gives wrong code for > 0:
13: invokespecial #40 // Method execute:()I
16: ifle 21
19: iconst_1
20: ireturn
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