Can Java class files use reserved keywords as names?

I'm aware that Java-the-compilable-programming-language is not one and the same as Java-the-bytecode-format-for-JVM-execution. There are examples of things that are valid in the .class format but not in the .java source code, such as constructor-less classes and synthetic methods.

1. If we hand-craft a .class file with a reserved Java language keyword (e.g. int, while) as the class, method, or field name, will the Java virtual machine accept it for loading?

2. If the class is loaded, does it imply that the only way to access this class or member is through Java reflection, because the name is syntactically illegal in the Java programming language?

The only restrictions on class names at the bytecode level are that they can't contain the characters [, . or ; and that they're at most 65535 bytes long. Among other things, this means that you can freely use reserved words, whitespace, special characters, Unicode, or even weird stuff like newlines.

You can theoretically even use null characters in a class name, but since it's impossible to have a null character in the filename, you can't include such a classfile in a jar. You might be able to create and load one dynamically though.

Here's an example of some of the things that you can do (written in Krakatau assembly):

; Entry point for the jar
.class Main
.super java/lang/Object

.method public static main : ([Ljava/lang/String;)V
    .limit stack 10
    .limit locals 10
    invokestatic int                                hello ()V
    invokestatic "-42"                              hello ()V
    invokestatic ""                                 hello ()V
    invokestatic "  some  whitespace and \t tabs"   hello ()V
    invokestatic "new\nline"                        hello ()V
    invokestatic 'name with "Quotes" in it'         hello ()V
    return
.end method
.end class


.class int
.super java/lang/Object
.method public static hello : ()V
    .limit stack 2
    .limit locals 0
    getstatic java/lang/System out Ljava/io/PrintStream;
    ldc "Hello from int"
    invokevirtual java/io/PrintStream println (Ljava/lang/Object;)V
    return
.end method
.end class

.class "-42"
.super java/lang/Object
.method public static hello : ()V
    .limit stack 2
    .limit locals 0
    getstatic java/lang/System out Ljava/io/PrintStream;
    ldc "Hello from -42"
    invokevirtual java/io/PrintStream println (Ljava/lang/Object;)V
    return
.end method
.end class

; Even the empty string can be a class name!
.class ""
.super java/lang/Object
.method public static hello : ()V
    .limit stack 2
    .limit locals 0
    getstatic java/lang/System out Ljava/io/PrintStream;
    ldc "Hello from "
    invokevirtual java/io/PrintStream println (Ljava/lang/Object;)V
    return
.end method
.end class

.class "  some  whitespace and \t tabs"
.super java/lang/Object
.method public static hello : ()V
    .limit stack 2
    .limit locals 0
    getstatic java/lang/System out Ljava/io/PrintStream;
    ldc "Hello from   some  whitespace and \t tabs"
    invokevirtual java/io/PrintStream println (Ljava/lang/Object;)V
    return
.end method
.end class

.class "new\nline"
.super java/lang/Object
.method public static hello : ()V
    .limit stack 2
    .limit locals 0
    getstatic java/lang/System out Ljava/io/PrintStream;
    ldc "Hello from new\nline"
    invokevirtual java/io/PrintStream println (Ljava/lang/Object;)V
    return
.end method
.end class

.class 'name with "Quotes" in it'
.super java/lang/Object
.method public static hello : ()V
    .limit stack 2
    .limit locals 0
    getstatic java/lang/System out Ljava/io/PrintStream;
    ldc "Hello from name with \"Quotes\" in it"
    invokevirtual java/io/PrintStream println (Ljava/lang/Object;)V
    return
.end method
.end class

Execution output:

Hello from int
Hello from -42
Hello from
Hello from   some  whitespace and        tabs
Hello from new
line
Hello from name with "Quotes" in it

See Holger's answer for the exact quote of the rules from the JVM specification.