Introduction to the class File Format

03_projects/pjba/01_src/main/java/org/isk/jvmhardcore/pjba/structure/ClassFile.java

@@ -0,0 +1,21 @@
+package org.isk.jvmhardcore.pjba.structure;
+
+import org.isk.jvmhardcore.pjba.structure.attribute.Attribute;
+
+public class ClassFile {
+  final private int magic = 0xcafebabe;
+  final private int version = 0x30; // 48.0 = 0x00 (version mineure) | 0x30 (version majeur)
+  private int constantPoolCount;
+  private Constant.ConstantPoolEntry[] constantPool;
+  final private int accessFlags = 0x0001 | 0x0020; // public super;
+  private int thisClass;
+  private int superClass;
+  private int interfacesCount;
+  private int[] interfaces;
+  private int fieldsCount;
+  private Field[] fields;
+  private int methodsCount;
+  private Method[] methods;
+  private int attributesCount;
+  private Attribute[] attributes;
+}

03_projects/pjba/01_src/main/java/org/isk/jvmhardcore/pjba/structure/Constant.java

@@ -0,0 +1,98 @@
+package org.isk.jvmhardcore.pjba.structure;
+
+public class Constant {
+  public static abstract class ConstantPoolEntry {
+    final private int tag;
+
+    public ConstantPoolEntry(ConstantPoolTag tag) {
+      this.tag = tag.getValue();
+    }
+  }
+
+  public static class UTF8 extends ConstantPoolEntry {
+    final private java.lang.String value;
+
+    public UTF8(final java.lang.String value) {
+      super(ConstantPoolTag.UTF8);
+      this.value = value;
+    }
+  }
+
+  public static class Integer extends ConstantPoolEntry {
+    final private int integer;
+
+    public Integer(int integer) {
+      super(ConstantPoolTag.INTEGER);
+      this.integer = integer;
+    }
+  }
+
+  public static class Float extends ConstantPoolEntry {
+    final private float floatValue;
+
+    public Float(float floatValue) {
+      super(ConstantPoolTag.FLOAT);
+      this.floatValue = floatValue;
+    }
+  }
+
+  public static class Long extends ConstantPoolEntry {
+    final private long longValue;
+
+    public Long(long longValue) {
+      super(ConstantPoolTag.LONG);
+      this.longValue = longValue;
+    }
+  }
+
+  public static class Double extends ConstantPoolEntry {
+    final private double doubleValue;
+
+    public Double(double doubleValue) {
+      super(ConstantPoolTag.DOUBLE);
+      this.doubleValue = doubleValue;
+    }
+  }
+
+  public static class Class extends ConstantPoolEntry {
+    final private int nameIndex;
+
+    public Class(final int nameIndex) {
+      super(ConstantPoolTag.CLASS);
+      this.nameIndex = nameIndex;
+    }
+  }
+
+  public static class String extends ConstantPoolEntry {
+    final private int utf8Index;
+
+    public String(int stringIndex) {
+      super(ConstantPoolTag.STRING);
+      this.utf8Index = stringIndex;
+    }
+  }
+
+  public static enum ConstantPoolTag {
+    UTF8(1),
+    INTEGER(3),
+    FLOAT(4),
+    LONG(5),
+    DOUBLE(6),
+    CLASS(7),
+    STRING(8),
+    FIELDREF(9),
+    METHODREF(10),
+    INTERFACE_METHODREF(11),
+    NAME_AND_TYPE(12);
+
+    private int value;
+
+    private ConstantPoolTag(int value) {
+      this.value = value;
+    }
+
+    public int getValue() {
+      return this.value;
+    }
+  }
+}

03_projects/pjba/01_src/main/java/org/isk/jvmhardcore/pjba/structure/Exception.java

@@ -0,0 +1,5 @@
+package org.isk.jvmhardcore.pjba.structure;
+
+public class Exception {
+
+}

03_projects/pjba/01_src/main/java/org/isk/jvmhardcore/pjba/structure/Field.java

@@ -0,0 +1,5 @@
+package org.isk.jvmhardcore.pjba.structure;
+
+public class Field {
+
+}

03_projects/pjba/01_src/main/java/org/isk/jvmhardcore/pjba/structure/Method.java

@@ -0,0 +1,11 @@
+package org.isk.jvmhardcore.pjba.structure;
+
+import org.isk.jvmhardcore.pjba.structure.attribute.Attribute;
+
+public class Method {
+  private int accessFlags = 0x0001 | 0x0008; // public static
+  private int nameIndex;
+  private int descriptorIndex;
+  private int attributesCount;
+  private Attribute[] attributes;
+}

03_projects/pjba/01_src/main/java/org/isk/jvmhardcore/pjba/structure/attribute/Attribute.java

@@ -0,0 +1,10 @@
+package org.isk.jvmhardcore.pjba.structure.attribute;
+
+public abstract class Attribute {
+  final private int nameIndex;
+  private int attributeLength;
+
+  public Attribute(final int nameIndex) {
+    this.nameIndex = nameIndex;
+  }
+}

03_projects/pjba/01_src/main/java/org/isk/jvmhardcore/pjba/structure/attribute/Code.java

@@ -0,0 +1,20 @@
+package org.isk.jvmhardcore.pjba.structure.attribute;
+
+import org.isk.jvmhardcore.pjba.structure.Exception;
+
+public class Code extends Attribute {
+  public final static String ATTRIBUTE_NAME = "Code";
+
+  private int maxStack;
+  private int maxLocals;
+  private int codeLength;
+  private byte[] code;
+  private int exceptionsCount;
+  private Exception[] exceptions;
+  private int attributesCount;
+  private Attribute[] attributes;
+
+  public Code(final int attributeNameIndex) {
+    super(attributeNameIndex);
+  }
+}

03_projects/pjba/build.xml

@@ -0,0 +1,13 @@
+<project name="pjba" default="archive" xmlns:plume="http://blog.soat.fr/ant-macros">
+  <import file="../../01_conf/targets.xml" />
+  <description>Plume Java Bytecode Assembler</description>
+
+  <target name="compile" depends="-init">
+    <echo>Compiling Main</echo>
+    <plume:compiler srcDir="${src.main.java.dir}" destDir="${build.classes.dir}" />
+  </target>
+
+  <target name="test" depends="compile">
+    <!-- Do nothing for now -->
+  </target>
+</project>

README.md

@@ -222,4 +222,13 @@ Unicode and Java.
 ### Compile and execute
 The project can only be executed through unit tests. (See introduction)
 
-Blog post: [Part 10 - L'unicode et Java](http://blog.soat.fr/2014/01/jvm-hardcore-part-10-unicode-et-java)
+Blog post: [JVM Hardcore - Part 10 - L'unicode et Java](http://blog.soat.fr/2014/01/11-jvm-hardcore-part-10-unicode-et-java)
+
+## part11
+### Summary
+Introduction to the `class` File Format.
+
+### Compile and execute
+Nothing to test. The project **pjba** contains only beans representing the structure of a class file.
+
+Blog post: [JVM Hardcore - Part 11 - Bytecode - Format d'un fichier .class](http://blog.soat.fr/2014/01/12-jvm-hardcore-part-11-bytecode-format-fichier-class)

build.xml

@@ -13,6 +13,7 @@
     <ant dir="${projects.dir}/bytecode/" target="${target}"  inheritAll="false" />
     <ant dir="${projects.dir}/mathparser/" target="${target}"  inheritAll="false" />
     <ant dir="${projects.dir}/encoding/" target="${target}"  inheritAll="false"/>
+    <ant dir="${projects.dir}/pjba/" target="${target}"  inheritAll="false" />
   </target>
 
   <target name="nop" description="Checks projects build">