Asif Ansari
Reputation: 27
Getting NullPointerException while invoking a Rule for a method having argument as Long
I am getting a NPE in my application while using a Byteman rule. I created a test java code and simulated the same issue, call to method m2 is generating NPE Version: /projects/byteman-download-4.0.23
Following is the java code:
import java.util.*;
public class npe {
public static void main(String args[]) {
Long l=System.currentTimeMillis();
Long lx=null;
m1(l);
m2(lx);
}
static void m1(Long l1)
{
System.out.println("l1 = " + l1);
}
static void m2(Long l2)
{
System.out.println("l2 new = " + l2);
}
}
Following is the byteman script:
RULE catch.npe.m1
CLASS npe
METHOD m1
COMPILE
AT ENTRY
IF true
DO
System.out.println("[BMAN] Got Method Trigger: m1 [" + $1 + "]");
ENDRULE
RULE catch.npe.m2
CLASS npe
METHOD m2
COMPILE
AT ENTRY
IF true
DO
System.out.println("[BMAN] Got Method Trigger: m2 [" + $1 + "]");
ENDRULE
Now executing the java program:
[root@asif-me btest]# java -Dorg.jboss.byteman.verbose -Dorg.jboss.byteman.dump.generated.classes -Dorg.jboss.byteman.dump.generated.classes.directory=/projects/tools/btest/decomp -javaagent:${BYTEMAN_HOME}/lib/byteman.jar=script:npe.btm -Dorg.jboss.byteman.compile.to.bytecode npe
AccessManager:init Initialising JDK9 AccessManager
AccessManager:init created module
AccessManager:init added extraReads
org.jboss.byteman.agent.Transformer : Saving transformed bytes to /projects/tools/btest/decomp/org/jboss/byteman/jigsaw/JigsawAccessEnabler.class
AccessManager:init returning JigsawAccessEnabler
org.jboss.byteman.agent.Transformer : possible trigger for rule catch.npe.m2 in class npe
RuleTriggerMethodAdapter.injectTriggerPoint : inserting trigger into npe.m2(java.lang.Long) void for rule catch.npe.m2
org.jboss.byteman.agent.Transformer : inserted trigger for catch.npe.m2 in class npe
org.jboss.byteman.agent.Transformer : possible trigger for rule catch.npe.m1 in class npe
RuleTriggerMethodAdapter.injectTriggerPoint : inserting trigger into npe.m1(java.lang.Long) void for rule catch.npe.m1
org.jboss.byteman.agent.Transformer : inserted trigger for catch.npe.m1 in class npe
org.jboss.byteman.agent.Transformer : Saving transformed bytes to /projects/tools/btest/decomp/npe.class
Rule.execute called for catch.npe.m1_0:0
org.jboss.byteman.agent.Transformer : Saving transformed bytes to /projects/tools/btest/decomp/org/jboss/byteman/rule/helper/Helper_HelperAdapter_Compiled_1.class
HelperManager.install for helper class org.jboss.byteman.rule.helper.Helper
calling activated() for helper class org.jboss.byteman.rule.helper.Helper
Default helper activated
calling installed(catch.npe.m1) for helper classorg.jboss.byteman.rule.helper.Helper
Installed rule using default helper : catch.npe.m1
catch.npe.m1 execute()
[BMAN] Got Method Trigger: m1 [1727221411198]
l1 = 1727221411198
Rule.execute called for catch.npe.m2_1:0
org.jboss.byteman.agent.Transformer : Saving transformed bytes to /projects/tools/btest/decomp/org/jboss/byteman/rule/helper/Helper_HelperAdapter_Compiled_2.class
HelperManager.install for helper class org.jboss.byteman.rule.helper.Helper
calling installed(catch.npe.m2) for helper classorg.jboss.byteman.rule.helper.Helper
Installed rule using default helper : catch.npe.m2
catch.npe.m2 execute()
catch.npe.m2 : java.lang.NullPointerException
caught ExecuteException
Exception in thread "main" org.jboss.byteman.rule.exception.ExecuteException: catch.npe.m2 : caught java.lang.NullPointerException
at org.jboss.byteman.rule.Rule.execute(Rule.java:852)
at org.jboss.byteman.rule.Rule.execute(Rule.java:789)
at npe.m2(npe.java)
at npe.main(npe.java:9)
Caused by: java.lang.NullPointerException
at org.jboss.byteman.rule.helper.Helper_HelperAdapter_Compiled_2.execute(npe.btm)
at org.jboss.byteman.rule.Rule.execute(Rule.java:820)
... 3 more
[root@asif-me btest]#
The generated code from dumped class file:
[root@asif-me decomp]# javap -v -p -s -c npe.class
Classfile /projects/tools/btest/decomp/npe.class
Last modified Sep 25, 2024; size 1806 bytes
MD5 checksum 7160079c97164a866b71ec6497fec007
Compiled from "npe.java"
public class npe
minor version: 0
major version: 55
flags: (0x0021) ACC_PUBLIC, ACC_SUPER
this_class: #2 // npe
super_class: #4 // java/lang/Object
interfaces: 0, fields: 0, methods: 4, attributes: 3
Constant pool:
#1 = Utf8 npe
#2 = Class #1 // npe
#3 = Utf8 java/lang/Object
#4 = Class #3 // java/lang/Object
#5 = Utf8 npe.java
#6 = Utf8 java/lang/invoke/MethodHandles$Lookup
#7 = Class #6 // java/lang/invoke/MethodHandles$Lookup
#8 = Utf8 java/lang/invoke/MethodHandles
#9 = Class #8 // java/lang/invoke/MethodHandles
#10 = Utf8 Lookup
#11 = Utf8 <init>
#12 = Utf8 ()V
#13 = NameAndType #11:#12 // "<init>":()V
#14 = Methodref #4.#13 // java/lang/Object."<init>":()V
#15 = Utf8 main
#16 = Utf8 ([Ljava/lang/String;)V
#17 = Utf8 java/lang/System
#18 = Class #17 // java/lang/System
#19 = Utf8 currentTimeMillis
#20 = Utf8 ()J
#21 = NameAndType #19:#20 // currentTimeMillis:()J
#22 = Methodref #18.#21 // java/lang/System.currentTimeMillis:()J
#23 = Utf8 java/lang/Long
#24 = Class #23 // java/lang/Long
#25 = Utf8 valueOf
#26 = Utf8 (J)Ljava/lang/Long;
#27 = NameAndType #25:#26 // valueOf:(J)Ljava/lang/Long;
#28 = Methodref #24.#27 // java/lang/Long.valueOf:(J)Ljava/lang/Long;
#29 = Utf8 m1
#30 = Utf8 (Ljava/lang/Long;)V
#31 = NameAndType #29:#30 // m1:(Ljava/lang/Long;)V
#32 = Methodref #2.#31 // npe.m1:(Ljava/lang/Long;)V
#33 = Utf8 m2
#34 = NameAndType #33:#30 // m2:(Ljava/lang/Long;)V
#35 = Methodref #2.#34 // npe.m2:(Ljava/lang/Long;)V
#36 = Utf8 catch.npe.m1_0:0
#37 = String #36 // catch.npe.m1_0:0
#38 = Utf8 org/jboss/byteman/rule/Rule
#39 = Class #38 // org/jboss/byteman/rule/Rule
#40 = Utf8 execute
#41 = Utf8 (Ljava/lang/String;Ljava/lang/Object;[Ljava/lang/Object;)V
#42 = NameAndType #40:#41 // execute:(Ljava/lang/String;Ljava/lang/Object;[Ljava/lang/Object;)V
#43 = Methodref #39.#42 // org/jboss/byteman/rule/Rule.execute:(Ljava/lang/String;Ljava/lang/Object;[Ljava/lang/Object;)V
#44 = Utf8 org/jboss/byteman/rule/exception/EarlyReturnException
#45 = Class #44 // org/jboss/byteman/rule/exception/EarlyReturnException
#46 = Utf8 org/jboss/byteman/rule/exception/ThrowException
#47 = Class #46 // org/jboss/byteman/rule/exception/ThrowException
#48 = Utf8 org/jboss/byteman/rule/exception/ExecuteException
#49 = Class #48 // org/jboss/byteman/rule/exception/ExecuteException
#50 = Utf8 out
#51 = Utf8 Ljava/io/PrintStream;
#52 = NameAndType #50:#51 // out:Ljava/io/PrintStream;
#53 = Fieldref #18.#52 // java/lang/System.out:Ljava/io/PrintStream;
#54 = Utf8 l1 = \u0001
#55 = String #54 // l1 = \u0001
#56 = Utf8 java/lang/invoke/StringConcatFactory
#57 = Class #56 // java/lang/invoke/StringConcatFactory
#58 = Utf8 makeConcatWithConstants
#59 = Utf8 (Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/invoke/CallSite;
#60 = NameAndType #58:#59 // makeConcatWithConstants:(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/invoke/CallSite;
#61 = Methodref #57.#60 // java/lang/invoke/StringConcatFactory.makeConcatWithConstants:(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/invoke/CallSite;
#62 = MethodHandle 6:#61 // REF_invokeStatic java/lang/invoke/StringConcatFactory.makeConcatWithConstants:(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/invoke/CallSite;
#63 = Utf8 (Ljava/lang/Long;)Ljava/lang/String;
#64 = NameAndType #58:#63 // makeConcatWithConstants:(Ljava/lang/Long;)Ljava/lang/String;
#65 = InvokeDynamic #0:#64 // #0:makeConcatWithConstants:(Ljava/lang/Long;)Ljava/lang/String;
#66 = Utf8 java/io/PrintStream
#67 = Class #66 // java/io/PrintStream
#68 = Utf8 println
#69 = Utf8 (Ljava/lang/String;)V
#70 = NameAndType #68:#69 // println:(Ljava/lang/String;)V
#71 = Methodref #67.#70 // java/io/PrintStream.println:(Ljava/lang/String;)V
#72 = Utf8 caught ReturnException
#73 = String #72 // caught ReturnException
#74 = Utf8 caught ThrowException
#75 = String #74 // caught ThrowException
#76 = Utf8 getThrowable
#77 = Utf8 ()Ljava/lang/Throwable;
#78 = NameAndType #76:#77 // getThrowable:()Ljava/lang/Throwable;
#79 = Methodref #47.#78 // org/jboss/byteman/rule/exception/ThrowException.getThrowable:()Ljava/lang/Throwable;
#80 = Utf8 caught ExecuteException
#81 = String #80 // caught ExecuteException
#82 = Utf8 catch.npe.m2_1:0
#83 = String #82 // catch.npe.m2_1:0
#84 = Utf8 l2 new = \u0001
#85 = String #84 // l2 new = \u0001
#86 = InvokeDynamic #1:#64 // #1:makeConcatWithConstants:(Ljava/lang/Long;)Ljava/lang/String;
#87 = Utf8 Code
#88 = Utf8 LineNumberTable
#89 = Utf8 StackMapTable
#90 = Utf8 InnerClasses
#91 = Utf8 SourceFile
#92 = Utf8 BootstrapMethods
{
public npe();
descriptor: ()V
flags: (0x0001) ACC_PUBLIC
Code:
stack=1, locals=1, args_size=1
0: aload_0
1: invokespecial #14 // Method java/lang/Object."<init>":()V
4: return
LineNumberTable:
line 3: 0
public static void main(java.lang.String[]);
descriptor: ([Ljava/lang/String;)V
flags: (0x0009) ACC_PUBLIC, ACC_STATIC
Code:
stack=2, locals=3, args_size=1
0: invokestatic #22 // Method java/lang/System.currentTimeMillis:()J
3: invokestatic #28 // Method java/lang/Long.valueOf:(J)Ljava/lang/Long;
6: astore_1
7: aconst_null
8: astore_2
9: aload_1
10: invokestatic #32 // Method m1:(Ljava/lang/Long;)V
13: aload_2
14: invokestatic #35 // Method m2:(Ljava/lang/Long;)V
17: return
LineNumberTable:
line 5: 0
line 6: 7
line 8: 9
line 9: 13
line 10: 17
static void m1(java.lang.Long);
descriptor: (Ljava/lang/Long;)V
flags: (0x0008) ACC_STATIC
Code:
stack=6, locals=1, args_size=1
0: ldc #37 // String catch.npe.m1_0:0
2: aconst_null
3: iconst_1
4: anewarray #4 // class java/lang/Object
7: dup
8: iconst_0
9: aload_0
10: aastore
11: invokestatic #43 // Method org/jboss/byteman/rule/Rule.execute:(Ljava/lang/String;Ljava/lang/Object;[Ljava/lang/Object;)V
14: getstatic #53 // Field java/lang/System.out:Ljava/io/PrintStream;
17: aload_0
18: invokedynamic #65, 0 // InvokeDynamic #0:makeConcatWithConstants:(Ljava/lang/Long;)Ljava/lang/String;
23: invokevirtual #71 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
26: return
27: getstatic #53 // Field java/lang/System.out:Ljava/io/PrintStream;
30: ldc #73 // String caught ReturnException
32: invokevirtual #71 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
35: pop
36: return
37: getstatic #53 // Field java/lang/System.out:Ljava/io/PrintStream;
40: ldc #75 // String caught ThrowException
42: invokevirtual #71 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
45: invokevirtual #79 // Method org/jboss/byteman/rule/exception/ThrowException.getThrowable:()Ljava/lang/Throwable;
48: athrow
49: getstatic #53 // Field java/lang/System.out:Ljava/io/PrintStream;
52: ldc #81 // String caught ExecuteException
54: invokevirtual #71 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
57: athrow
Exception table:
from to target type
0 14 27 Class org/jboss/byteman/rule/exception/EarlyReturnException
0 14 37 Class org/jboss/byteman/rule/exception/ThrowException
0 14 49 Class org/jboss/byteman/rule/exception/ExecuteException
StackMapTable: number_of_entries = 3
frame_type = 91 /* same_locals_1_stack_item */
stack = [ class org/jboss/byteman/rule/exception/EarlyReturnException ]
frame_type = 73 /* same_locals_1_stack_item */
stack = [ class org/jboss/byteman/rule/exception/ThrowException ]
frame_type = 75 /* same_locals_1_stack_item */
stack = [ class org/jboss/byteman/rule/exception/ExecuteException ]
LineNumberTable:
line 14: 14
line 15: 26
static void m2(java.lang.Long);
descriptor: (Ljava/lang/Long;)V
flags: (0x0008) ACC_STATIC
Code:
stack=6, locals=1, args_size=1
0: ldc #83 // String catch.npe.m2_1:0
2: aconst_null
3: iconst_1
4: anewarray #4 // class java/lang/Object
7: dup
8: iconst_0
9: aload_0
10: aastore
11: invokestatic #43 // Method org/jboss/byteman/rule/Rule.execute:(Ljava/lang/String;Ljava/lang/Object;[Ljava/lang/Object;)V
14: getstatic #53 // Field java/lang/System.out:Ljava/io/PrintStream;
17: aload_0
18: invokedynamic #86, 0 // InvokeDynamic #1:makeConcatWithConstants:(Ljava/lang/Long;)Ljava/lang/String;
23: invokevirtual #71 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
26: return
27: getstatic #53 // Field java/lang/System.out:Ljava/io/PrintStream;
30: ldc #73 // String caught ReturnException
32: invokevirtual #71 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
35: pop
36: return
37: getstatic #53 // Field java/lang/System.out:Ljava/io/PrintStream;
40: ldc #75 // String caught ThrowException
42: invokevirtual #71 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
45: invokevirtual #79 // Method org/jboss/byteman/rule/exception/ThrowException.getThrowable:()Ljava/lang/Throwable;
48: athrow
49: getstatic #53 // Field java/lang/System.out:Ljava/io/PrintStream;
52: ldc #81 // String caught ExecuteException
54: invokevirtual #71 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
57: athrow
Exception table:
from to target type
0 14 27 Class org/jboss/byteman/rule/exception/EarlyReturnException
0 14 37 Class org/jboss/byteman/rule/exception/ThrowException
0 14 49 Class org/jboss/byteman/rule/exception/ExecuteException
StackMapTable: number_of_entries = 3
frame_type = 91 /* same_locals_1_stack_item */
stack = [ class org/jboss/byteman/rule/exception/EarlyReturnException ]
frame_type = 73 /* same_locals_1_stack_item */
stack = [ class org/jboss/byteman/rule/exception/ThrowException ]
frame_type = 75 /* same_locals_1_stack_item */
stack = [ class org/jboss/byteman/rule/exception/ExecuteException ]
LineNumberTable:
line 19: 14
line 20: 26
}
InnerClasses:
public static final #10= #7 of #9; // Lookup=class java/lang/invoke/MethodHandles$Lookup of class java/lang/invoke/MethodHandles
SourceFile: "npe.java"
BootstrapMethods:
0: #62 REF_invokeStatic java/lang/invoke/StringConcatFactory.makeConcatWithConstants:(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/invoke/CallSite;
Method arguments:
#55 l1 = \u0001
1: #62 REF_invokeStatic java/lang/invoke/StringConcatFactory.makeConcatWithConstants:(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/invoke/CallSite;
Method arguments:
#85 l2 new = \u0001
Why NPE is generated ? Seems when rule is invoked, it is trying to pass null to native long, instead of Long.
Upvotes: 0
Views: 29
Answers (1)
Asif Ansari
Reputation: 27
This issue is fixed now in 4.0.24. issues.redhat.com/browse/BYTEMAN-443
Upvotes: 0