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  1. Byteman
  2. BYTEMAN-443

NullPointerException while invoking a Rule for a method having argument as Long

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    • User Experience

      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.
       

              rhn-engineering-adinn Andrew Dinn
              narendrasingh2 Narendra SINGH2
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                Created:
                Updated:
                Resolved: