Легко сделать это самостоятельно, если вы знаете спецификацию .
Вот быстрая и грязная демонстрационная программа, как это сделать:
package test;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.*;
public class Main {
private static Map<Integer, String> strings = new HashMap<Integer, String>();
private static Set<Integer> classes = new HashSet<Integer>();
private static int indexCorrection = 0; // for correcting indexes to constant pools with long and double entries
public static void main(String[] args) throws Exception {
printReferencedClassesFromClass(String.class);
}
private static void printReferencedClassesFromClass(Class<?> c) throws IOException {
saveReferencedClassesFromStream(c.getResourceAsStream(c.getSimpleName() + ".class"));
printReferencedClasses();
}
private static void printReferencedClasses() {
for (Integer index : classes)
System.out.println(strings.get(index));
}
private static void saveReferencedClassesFromStream(InputStream stream) throws IOException {
DataInputStream dataStream = new DataInputStream(stream);
skipHeader(dataStream);
saveReferencedClassesFromConstantPool(dataStream);
}
private static void skipHeader(DataInputStream dataInputStream) throws IOException {
readU4(dataInputStream); // magic byte
readU2(dataInputStream); // minor version
readU2(dataInputStream); // major version
}
private static void saveReferencedClassesFromConstantPool(DataInputStream stream) throws IOException {
int poolSize = readU2(stream);
for (int n = 1; n < poolSize - indexCorrection; n++)
savePoolEntryIfIsClassReference(n, stream);
}
private static void savePoolEntryIfIsClassReference(int index, DataInputStream stream) throws IOException {
int tag = readU1(stream);
switch (tag) {
case 1: // Utf8
saveStringFromUtf8Entry(index, stream);
break;
case 7: // Class
saveClassEntry(stream);
break;
case 8: // String
case 16: // MethodType
readU2(stream);
break;
case 3: // Integer
case 4: // Float
readU4(stream);
break;
case 5: // Long
case 6: // Double
readU4(stream);
readU4(stream);
indexCorrection++;
break;
case 9: // Fieldref
case 10: // Methodref
case 11: // InterfaceMethodref
case 12: // NameAndType
case 18: // InvokeDynmaic
readU2(stream);
readU2(stream);
break;
case 15: // MethodHandle
readU1(stream);
readU2(stream);
break;
}
}
private static void saveClassEntry(DataInputStream stream) throws IOException {
classes.add(readU2(stream));
}
private static void saveStringFromUtf8Entry(int index, DataInputStream stream) throws IOException {
strings.put(index + indexCorrection, readString(stream));
}
private static String readString(DataInputStream stream) throws IOException {
return stream.readUTF();
}
private static int readU1(DataInputStream stream) throws IOException {
return stream.readUnsignedByte();
}
private static int readU2(DataInputStream stream) throws IOException {
return stream.readUnsignedShort();
}
private static int readU4(DataInputStream stream) throws IOException {
return stream.readInt();
}
}
Вывод:
test/Main
java/lang/Object
java/io/BufferedInputStream
java/util/Iterator
java/io/FileInputStream
java/lang/System
java/lang/Integer
java/lang/Exception
java/lang/String
java/io/File
java/util/Map
java/util/HashMap
java/io/IOException
java/util/Set
java/io/DataInputStream
java/io/PrintStream
java/util/HashSet
java/lang/Throwable