JDK-8211147 : Incorrect comparator com.sun.beans.introspect.MethodInfo.MethodOrder
  • Type: Bug
  • Component: client-libs
  • Sub-Component: java.beans
  • Affected Version: 9,10.0.2,11,12
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • OS: os_x
  • CPU: x86
  • Submitted: 2018-09-08
  • Updated: 2022-01-18
  • Resolved: 2018-12-01
The Version table provides details related to the release that this issue/RFE will be addressed.

Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.

To download the current JDK release, click here.
JDK 11 JDK 12
11.0.6-oracleFixed 12 b23Fixed
Related Reports
Relates :  
Description
ADDITIONAL SYSTEM INFORMATION :
macOS 10.13.6 (17G65) (but the bug is reproducible on Linux too)

$ java -version
java version "10.0.2" 2018-07-17
Java(TM) SE Runtime Environment 18.3 (build 10.0.2+13)
Java HotSpot(TM) 64-Bit Server VM 18.3 (build 10.0.2+13, mixed mode)

A DESCRIPTION OF THE PROBLEM :
Method java.beans.Introspector.getBeanInfo(...) sometimes thows exception for complex classes.
getBeanInfo sort methods, but comparator violates its contract (sgn(compare(x, y)) == -sgn(compare(y, x)) for all x, y), so sort can throw IllegalArgumentException

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run program many times (1000 should be enough)
for i in `seq 1000`; do java bug.Main; done

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
No exceptions expected
ACTUAL -
3-4 times program crashes with exception:
Exception in thread "main" java.lang.IllegalArgumentException: Comparison method violates its general contract!                                                                  ]
	at java.base/java.util.TimSort.mergeHi(TimSort.java:899)
	at java.base/java.util.TimSort.mergeAt(TimSort.java:516)
	at java.base/java.util.TimSort.mergeCollapse(TimSort.java:441)
	at java.base/java.util.TimSort.sort(TimSort.java:245)
	at java.base/java.util.Arrays.sort(Arrays.java:1514)
	at java.base/java.util.ArrayList.sort(ArrayList.java:1585)
	at java.desktop/com.sun.beans.introspect.MethodInfo.get(MethodInfo.java:94)
	at java.desktop/com.sun.beans.introspect.ClassInfo.getMethods(ClassInfo.java:71)
	at java.desktop/java.beans.Introspector.getTargetMethodInfo(Introspector.java:1046)
	at java.desktop/java.beans.Introspector.getBeanInfo(Introspector.java:462)
	at java.desktop/java.beans.Introspector.getBeanInfo(Introspector.java:205)
	at bug.Main.main(Main.java:14)

---------- BEGIN SOURCE ----------
package bug;

import java.beans.Introspector;
import java.io.Serializable;
import java.util.AbstractCollection;
import java.util.AbstractList;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.RandomAccess;

public class Main {
    public static void main(String[] args) throws Exception {
        Introspector.getBeanInfo(X.class);
    }

    interface X_1 {AbstractList x_8(); }interface X_2 {Cloneable x_0(); }interface X_3 {Serializable x_1(); }interface X_4 {Object x_7(); }interface X_5 {RandomAccess x_6(); }interface X_6 {RandomAccess x_0(); }interface X_7 {Serializable x_5(); }interface X_8 {Object x_4(); }interface X_9 {RandomAccess x_5(); }interface X_10 {Cloneable x_5(); }interface X_11 {RandomAccess x_9(); }interface X_12 {Cloneable x_9(); }interface X_13 {Iterable x_2(); }interface X_14 {Collection x_7(); }interface X_15 {Serializable x_4(); }interface X_16 {Cloneable x_7(); }interface X_17 {Object x_1(); }interface X_18 {ArrayList x_6(); }interface X_19 {List x_5(); }interface X_20 {Collection x_2(); }interface X_21 {List x_1(); }interface X_22 {List x_3(); }interface X_23 {RandomAccess x_3(); }interface X_24 {RandomAccess x_1(); }interface X_25 {Object x_6(); }interface X_26 {Cloneable x_7(); }interface X_27 {Iterable x_0(); }interface X_28 {Iterable x_1(); }interface X_29 {AbstractList x_7(); }interface X_30 {AbstractList x_1(); }interface X_31 {Cloneable x_9(); }interface X_32 {ArrayList x_6(); }interface X_33 {Cloneable x_2(); }interface X_34 {Iterable x_6(); }interface X_35 {Iterable x_9(); }interface X_36 {AbstractList x_9(); }interface X_37 {Iterable x_7(); }interface X_38 {Iterable x_3(); }interface X_39 {Iterable x_9(); }interface X_40 {AbstractList x_3(); }interface X_41 {List x_0(); }interface X_42 {Iterable x_0(); }interface X_43 {Iterable x_2(); }interface X_44 {ArrayList x_4(); }interface X_45 {AbstractList x_4(); }interface X_46 {Collection x_4(); }interface X_47 {ArrayList x_2(); }interface X_48 {ArrayList x_6(); }interface X_49 {Serializable x_1(); }interface X_50 {Cloneable x_7(); }interface X_51 {Collection x_5(); }interface X_52 {RandomAccess x_5(); }interface X_53 {Collection x_5(); }interface X_54 {RandomAccess x_4(); }interface X_55 {Collection x_0(); }interface X_56 {Collection x_7(); }interface X_57 {Iterable x_9(); }interface X_58 {List x_3(); }interface X_59 {Serializable x_7(); }interface X_60 {AbstractCollection x_6(); }interface X_61 {AbstractList x_9(); }interface X_62 {List x_7(); }interface X_63 {AbstractCollection x_3(); }interface X_64 {RandomAccess x_4(); }interface X_65 {Object x_3(); }interface X_66 {RandomAccess x_6(); }interface X_67 {Cloneable x_6(); }interface X_68 {Cloneable x_3(); }interface X_69 {Collection x_5(); }interface X_70 {AbstractCollection x_0(); }interface X_71 {Object x_8(); }interface X_72 {AbstractCollection x_3(); }interface X_73 {Serializable x_4(); }interface X_74 {AbstractList x_8(); }interface X_75 {ArrayList x_1(); }interface X_76 {List x_5(); }interface X_77 {Object x_0(); }interface X_78 {Collection x_0(); }interface X_79 {ArrayList x_2(); }interface X_80 {ArrayList x_8(); }interface X_81 {Cloneable x_3(); }interface X_82 {Serializable x_1(); }interface X_83 {List x_1(); }interface X_84 {Collection x_5(); }interface X_85 {RandomAccess x_9(); }interface X_86 {AbstractList x_3(); }interface X_87 {Cloneable x_6(); }interface X_88 {Object x_2(); }interface X_89 {ArrayList x_5(); }interface X_90 {Iterable x_1(); }interface X_91 {ArrayList x_4(); }interface X_92 {Iterable x_6(); }interface X_93 {Collection x_7(); }interface X_94 {Iterable x_2(); }interface X_95 {AbstractList x_7(); }interface X_96 {RandomAccess x_2(); }interface X_97 {RandomAccess x_2(); }interface X_98 {List x_6(); }interface X_99 {Object x_4(); }interface X_100 {Collection x_7(); }static class X implements X_1,X_2,X_3,X_4,X_5,X_6,X_7,X_8,X_9,X_10,X_11,X_12,X_13,X_14,X_15,X_16,X_17,X_18,X_19,X_20,X_21,X_22,X_23,X_24,X_25,X_26,X_27,X_28,X_29,X_30,X_31,X_32,X_33,X_34,X_35,X_36,X_37,X_38,X_39,X_40,X_41,X_42,X_43,X_44,X_45,X_46,X_47,X_48,X_49,X_50,X_51,X_52,X_53,X_54,X_55,X_56,X_57,X_58,X_59,X_60,X_61,X_62,X_63,X_64,X_65,X_66,X_67,X_68,X_69,X_70,X_71,X_72,X_73,X_74,X_75,X_76,X_77,X_78,X_79,X_80,X_81,X_82,X_83,X_84,X_85,X_86,X_87,X_88,X_89,X_90,X_91,X_92,X_93,X_94,X_95,X_96,X_97,X_98,X_99,X_100 {public ArrayList x_0() {return null;}
        public ArrayList x_1() {return null;}
        public ArrayList x_2() {return null;}
        public ArrayList x_3() {return null;}
        public ArrayList x_4() {return null;}
        public ArrayList x_5() {return null;}
        public ArrayList x_6() {return null;}
        public ArrayList x_7() {return null;}
        public ArrayList x_8() {return null;}
        public ArrayList x_9() {return null;}}
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
This patch should help
@@ -141,7 +141,10 @@
             if (aret.isAssignableFrom(bret)) {
                 return 1;
             }
-            return -1;
+            if (bret.isAssignableFrom(aret)) {
+                return -1;
+            }
+            return aret.getName().compareTo(bret.getName());
         }

         static final MethodOrder instance = new MethodOrder();


Comments
Fix request (11u) Requesting backport for Oracle 11.0.6 parity. Patch applies cleanly, without regressions.
11-11-2019

URL: http://hg.openjdk.java.net/jdk/jdk/rev/7644f534b60a User: psadhukhan Date: 2018-12-05 10:10:00 +0000
05-12-2018

The root cause is how this comparator compare the return types of the methods. The current code assumes that if two methods have the same names then one of the return type should be subtype of another, because of covariant return types. An example in this bug shows that it is not necessary correct, which means that this method may always returns "-1" if two return types are unrelated.
01-12-2018

URL: http://hg.openjdk.java.net/jdk/client/rev/7644f534b60a User: serb Date: 2018-11-30 23:55:31 +0000
01-12-2018

Workaround: System.setProperty("java.util.Arrays.useLegacyMergeSort", "true");
26-09-2018

does it affect 8u? 12?
26-09-2018

Could not reproduce the issue in macOS 10.13.5 and in Ubuntu 18.04.1 LTS using JDK 10.0.2+13. Did not get any exceptions. Ran the provided test case 'Main.java' 1000 times using "Runtime.getRuntime().exec("java Main");" from another java program (RunMultipleTimes.java).
26-09-2018