Class for printing class hierarchy as text

I'm coding a little class hierarchy printing tool for easy show hierarchies of java classes.

This is my current code:

`import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.TreeMap;

import javax.swing.JDialog;

import jdk.nashorn.internal.runtime.PropertyMap; // since Java 8, just for testing

import com.sun.javafx.collections.TrackableObservableList;

public class PrintClassHierarchy {
private static final String PADDING = " ";
private static final String PADDING_WITH_COLUMN = " | ";
private static final String PADDING_WITH_ENTRY = " |--- ";
private static final String BASE_CLASS = Object.class.getName();

private TreeMap> entries;
private boolean[] moreToCome;

public static void main(final String[] args) {
new PrintClassHierarchy().printHierarchy(
PrintStream.class,
FileOutputStream.class,
FileInputStream.class,
TrackableObservableList.class,
PropertyMap.class,
JDialog.class
);
}

public void printHierarchy(final Class... clazzes) {
// clean values
entries = new TreeMap<>();
moreToCome = new boolean[99];

// get all entries of tree
traverseClasses(clazzes);

// print collected entries as ASCII tree
printHierarchy(BASE_CLASS, 0);
}

private void printHierarchy(final String node, final int level) {
for (int i = 1; i 0) {
System.out.print(PADDING_WITH_ENTRY);
}

System.out.println(node);

if (entries.containsKey(node)) {
final List list = entries.get(node);

for (int i = 0; i ... clazzes) {
Arrays.asList(clazzes).forEach(c -> traverseClasses(c, 0));
}

private void traverseClasses(final Class clazz, final int level) {

Just two quick points (for the original code):

-
You could save a lot of logic with a TreeMultimap (from Google Guava):

private final TreeMultimap entries = TreeMultimap.create();

This:

if (entries.containsKey(node)) {
 final List list = entries.get(node);

 for (int i = 0; i < list.size(); i++) {
     moreToCome[level] = (i < list.size() - 1);
     printHierarchy(list.get(i), level + 1);
 }
}

could be replaced with

for (String e: list) {
    moreToCome[level] = (i < list.size() - 1);
    printHierarchy(e, level + 1);
    i++;
}

and this:

if (entries.containsKey(superName)) {
 final List list = entries.get(superName);

 if (!list.contains(name)) {
     list.add(name);
     Collections.sort(list); // SortedList
 }
} else {
 entries.put(superName, new ArrayList(Arrays.asList(name)));
}

could be replaced with

entries.put(superName, name);

(See also: Effective Java, 2nd edition, Item 47: Know and use the libraries The author mentions only the JDK's built-in libraries but I think the reasoning could be true for other libraries too.)

-
I'd try to add a boolean parameter (lastElementInThisLevel or something similar) to the printHierarchy method to remove the moreToCome array and clean this loop:

int i = 0;
for (String e: list) {
    moreToCome[level] = (i < list.size() - 1);
    printHierarchy(e, level + 1);
    i++;
}

(Use more descriptive names than list and e.)

StackExchange Code Review Q#46032, answer score: 5