FULL PRODUCT VERSION :
java version "1.5.0_05"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_05-b05)
Java HotSpot(TM) Client VM (build 1.5.0_05-b05, mixed mode, sharing)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
When compiling the following code, javac generates an AssertionError:

class Reference<T> {
T value;

Reference(T value) {
this.value = value;
}
}

public class GenericInABox {

public static void main(String[] args) {
Reference<Integer> reference = new Reference<Integer>(0);
reference.value++;
System.out.println(reference.value);
}
}


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1- Create a file names GenericInABox.java
2- Put the code below in the file and save.
/* ======================== */
class Reference<T> {
T value;

Reference(T value) {
this.value = value;
}
}

public class GenericInABox {

public static void main(String[] args) {
Reference<Integer> reference = new Reference<Integer>(0);
reference.value++;
System.out.println(reference.value);
}
}
/* ======================== */
3- on the command prompt execute the following line:
javac GenericInABox.java

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Something like:

GenericInABox.java:18: operator + cannot be applied to java.lang.Object,int
          reference.value += 1;
                           ^
ACTUAL -
An exception has occurred in the compiler (1.5.0_05). Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport) after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.AssertionError: (Integer)reference.value
at com.sun.tools.javac.comp.Lower.abstractLval(Lower.java:1853)
at com.sun.tools.javac.comp.Lower.lowerBoxedPostop(Lower.java:2659)
at com.sun.tools.javac.comp.Lower.visitUnary(Lower.java:2696)
at com.sun.tools.javac.tree.Tree$Unary.accept(Tree.java:910)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1881)
at com.sun.tools.javac.tree.TreeTranslator.visitExec(TreeTranslator.java:227)
at com.sun.tools.javac.tree.Tree$Exec.accept(Tree.java:728)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1881)
at com.sun.tools.javac.tree.TreeTranslator.translate(TreeTranslator.java:54)
at com.sun.tools.javac.tree.TreeTranslator.visitBlock(TreeTranslator.java:145)
at com.sun.tools.javac.comp.Lower.visitBlock(Lower.java:2927)
at com.sun.tools.javac.tree.Tree$Block.accept(Tree.java:535)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1881)
at com.sun.tools.javac.tree.TreeTranslator.visitMethodDef(TreeTranslator.java:129)
at com.sun.tools.javac.comp.Lower.visitMethodDefInternal(Lower.java:2267)
at com.sun.tools.javac.comp.Lower.visitMethodDef(Lower.java:2186)
at com.sun.tools.javac.tree.Tree$MethodDef.accept(Tree.java:478)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1881)
at com.sun.tools.javac.comp.Lower.visitClassDef(Lower.java:1989)
at com.sun.tools.javac.tree.Tree$ClassDef.accept(Tree.java:434)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1881)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1901)
at com.sun.tools.javac.comp.Lower.translateTopLevelClass(Lower.java:3064)
at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:496)
at com.sun.tools.javac.main.Main.compile(Main.java:592)
at com.sun.tools.javac.main.Main.compile(Main.java:544)
at com.sun.tools.javac.Main.compile(Main.java:67)
at com.sun.tools.javac.Main.main(Main.java:52)


ERROR MESSAGES/STACK TRACES THAT OCCUR :
An exception has occurred in the compiler (1.5.0_05). Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport) after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.AssertionError: (Integer)reference.value
at com.sun.tools.javac.comp.Lower.abstractLval(Lower.java:1853)
at com.sun.tools.javac.comp.Lower.lowerBoxedPostop(Lower.java:2659)
at com.sun.tools.javac.comp.Lower.visitUnary(Lower.java:2696)
at com.sun.tools.javac.tree.Tree$Unary.accept(Tree.java:910)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1881)
at com.sun.tools.javac.tree.TreeTranslator.visitExec(TreeTranslator.java:227)
at com.sun.tools.javac.tree.Tree$Exec.accept(Tree.java:728)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1881)
at com.sun.tools.javac.tree.TreeTranslator.translate(TreeTranslator.java:54)
at com.sun.tools.javac.tree.TreeTranslator.visitBlock(TreeTranslator.java:145)
at com.sun.tools.javac.comp.Lower.visitBlock(Lower.java:2927)
at com.sun.tools.javac.tree.Tree$Block.accept(Tree.java:535)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1881)
at com.sun.tools.javac.tree.TreeTranslator.visitMethodDef(TreeTranslator.java:129)
at com.sun.tools.javac.comp.Lower.visitMethodDefInternal(Lower.java:2267)
at com.sun.tools.javac.comp.Lower.visitMethodDef(Lower.java:2186)
at com.sun.tools.javac.tree.Tree$MethodDef.accept(Tree.java:478)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1881)
at com.sun.tools.javac.comp.Lower.visitClassDef(Lower.java:1989)
at com.sun.tools.javac.tree.Tree$ClassDef.accept(Tree.java:434)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1881)
at com.sun.tools.javac.comp.Lower.translate(Lower.java:1901)
at com.sun.tools.javac.comp.Lower.translateTopLevelClass(Lower.java:3064)
at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:496)
at com.sun.tools.javac.main.Main.compile(Main.java:592)
at com.sun.tools.javac.main.Main.compile(Main.java:544)
at com.sun.tools.javac.Main.compile(Main.java:67)
at com.sun.tools.javac.Main.main(Main.java:52)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
class Reference<T> {
T value;

Reference(T value) {
this.value = value;
}
}

public class GenericInABox {

public static void main(String[] args) {
Reference<Integer> reference = new Reference<Integer>(0);
reference.value++;
System.out.println(reference.value);
}
}

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

CUSTOMER SUBMITTED WORKAROUND :
Change the code to (to be able to get a regular compiler error)

class Reference<T> {
T value;

Reference(T value) {
this.value = value;
}
}

public class GenericInABox {

public static void main(String[] args) {
Reference<Integer> reference = new Reference<Integer>(0);
reference.value += 1;
System.out.println(reference.value);
}
}

or (to be able to run)

class Reference<T> {
T value;

Reference(T value) {
this.value = value;
}
}

public class GenericInABox {

public static void main(String[] args) {
Reference<Integer> reference = new Reference<Integer>(0);
reference.value = reference.value + 1;
System.out.println(reference.value);
}
}