the world is a pixel
Slides Resumos para a SCJP
O João Sávio, Embaixador de Campus da Sun na Unesp Rio Claro preparou vários resumos em slides para quem está estudando para a certificação SCJP. Eles me pareceram muito bons para quem já leu e já aprendeu o básico sobre o assunto e agora está busacando um material de fixação.
Aqui está um deles, o de Conjuntos e Tipos Genéricos:
O restante dos resumos você confere nesse post no blog do João Sávio.
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Android screen height and width
12 March, 2011 - 9:30 pm
Tags: Android, Java, mobile, programming, screensize
Posted in english | 1 comment
Context ctx = getContext(); Display display = ((WindowManager)ctx.getSystemService(ctx.WINDOW_SERVICE)).getDefaultDisplay(); int width = display.getWidth(); int height = display.getHeight(); Yes, there are easier ways to retrieve the screen width on Android but there are cases that this long code is the only solution. You may already have the Context. WindowManager or the Display and so it would be [...]
o blog é um caderno
29 November, 2010 - 11:45 am
Tags: Blog, Embaixador de Campus, idéias, Sun Microsystems
Posted in português | 3 comments
Eu sempre usei e fui entusiasta de se usar o blog como uma ferramenta de construção e compartilhamento de conhecimento livre. Somos capazes de criar coisas incríveis mas elas podem muito bem ficar aprisionadas para sempre nas folhas de papel de um caderno da faculdade. Usar um blog para anotações compartilhadas é uma excelente forma [...]
Java: invoking a method by name
29 April, 2010 - 10:29 am
Tags: Class, Java, method, programming, Reflection
Posted in english | 2 comments
import java.lang.reflect.*; public class Foo { public void bar(int param){ System.out.println(param); } public static void main(String args[]){ Object f = new Foo(); try { Method m = f.getClass().getMethod("bar", int.class); m.invoke(f, 42); } catch (Exception e){ System.err.println(e); } } } $ java Foo 42
calling commands in Java
8 April, 2010 - 1:09 pm
Tags: getruntime, Java, programming, runtime
Posted in english | No comments
I don’t like the approach of calling native shell commands in any language instead of using multi platform libraries, but here is a little prof of concept Java program to call native commands. import java.io.*; import java.util.*; public class Exec { public static void main(String args[]) throws IOException { Process proc = Runtime.getRuntime().e xec(args); BufferedReader [...]
Iterating over a HashMap
8 April, 2010 - 11:22 am
Tags: collections, enhanced loop, foreach, hashmap, iterating, Java, programming
Posted in english | No comments
Iterating over a HashMap using the enhanced loop (foreach) in Java is a good way to keep your code smaller, more legible and usually more semantically coherent. import java.util.HashMap; import java.util.Map; class Foo {} public class Main { public static void main(String args[]){ Map<Byte, Foo> mHash; mHash = new HashMap<Byte, Foo>(); [...]
Getting enviroment information on Android
16 March, 2010 - 10:18 am
Tags: Android, Eclipse, Java, programming, who am i, whoami
Posted in english | 8 comments
This is a simple program I wrote called Who Am I that shows informations about the device which it is running. Which can be useful for developers and maybe advanced users. Download: WhoAmI.tar.bz2 – Eclipse project. It’s configured for Android platform 4 (1.6) but should work without problems in newer Android platform versions. WhoAmI.apk – [...]
The Caps Lock Java Socket Server
27 February, 2010 - 9:39 pm
Tags: caps lock, Java, programming, socket, upcase
Posted in english | 3 comments
Here is a simple server for those who are starting studying sockets or just needs a simple socket server example for reuse while writing your own behavior. Features: A client should enter a string and the server would answer the same string, with each symbol in up case, when possible. Default port at 8080. One [...]
Beware the locale
22 February, 2010 - 5:16 pm
Tags: development, i18n, Java, JUnit, locale, programming, String, teste unitário, toString, unit testing
Posted in english | No comments
Today I was programming a toString method for a class widely used in a application, using the very useful String.format that provides a C’s like printf formatter. @Override public String toString() { return String.format("VO[a: %.1f, b: %.1f, c: %.1f]", a, b, a+b); } %.1f means a float with one digit precision after the dot separator. [...]
Java Font List
5 January, 2010 - 6:10 pm
Tags: AWT, fonts, Java, JVM, Larabie, Larabie Fonts, programming
Posted in english | Comments Off
Here’s a program that lists fonts available in your JVM. You can also set the environment variable JAVA_FONTS to specify the font directory. import java.awt.GraphicsEnvironment; public class ListFonts { public static void main(String args[]){ GraphicsEnvironment e = GraphicsEnvironment.getLocalGraphicsEnvironment(); for(String font:e.getAvailableFontFamilyNames()){ System.out.println(font); } } } By using pipes you can count how many fonts you [...]
Tiled TMX Map Loader for Pygame
I’m using the Tiled Map Editor for a while, I even wrote that tutorial about it. It’s a general purpose tile map editor, written in Java but now migrating to C++ with Qt, that can be easily used with my set of free pixelart tiles. A map done with Tiled is stored in a file [...]












