Easy to Learn Java: Programming Articles, Examples and Tips

Start with Java in a few days with Java Lessons or Lectures

Home

Code Examples

Java Tools

More Java Tools!

Java Forum

All Java Tips

Books

Submit News
Search the site here...
Search...
 
Search the JavaFAQ.nu
1000 Java Tips ebook

1000 Java Tips - Click here for the high resolution copy!1000 Java Tips - Click here for the high resolution copy!

Java Screensaver, take it here

Free "1000 Java Tips" eBook is here! It is huge collection of big and small Java programming articles and tips. Please take your copy here.

Take your copy of free "Java Technology Screensaver"!.

Easy Learn Java: Programming Articles, Examples and Tips - Page 521


Previous 1060 Stories (530 Pages, 2 Per Page) Next

How to unsign signed bytes in Java - your guide is here

Go to all tips in General Java

How to avoid problems with signed bytes? Unsign them.

We know that Java has signed bytes, we know Java, some people do not, many programs are not aware about Java at all and send unsigned bytes to Java program which waits for signed ones... what happens with your program? Whom your chief is going to blame? Of cause not James Gosling - YOU Smile

Yesterday I was recommending to one newbie in Java the "Identifiers and primitive data types" lecture as a good start with Java data types. But suddenly he asked me about signed bytes and how he is supposed to deal with them - in many other languages they are not signed. If someone writes a Java program which communicates with non Java program and sends bytes, so what happens?


Practical solution for Java signed bytes is below

Yes, maybe it is strange, maybe it is erratic, maybe it is bad. But it is just like this - Java has bytes, shorts, ints, and longs that are all signed.

-128...+127 - bytes range

the 8th bit which is (most significant) is used as a sign bit. 1 means 'negative', and 0 - 'positive'.

For example -128 is : 10000000
-125 is presented like so: 10000011 and so on.

Here is Java code example I use in my programs when I need to convert signed Java bytes into unsigned 'non Java' bytes. The code below changes range from -128... 127 to 0.... 255 and makes it possible to get "normal" integers Smile


Code:

function getUnsignedBytes(){
    byte[] bytes = getMyBytesFromSomewhere(); // here you get them here from some another place
    int length = bytes.length;
    for (int step = 0; step < length; step++){
        int byteValue = new Integer(bytes[step]).intValue( );
        if (byteValue < 0 ){
            byteValue = bytes[step] & 0x80;
            byteValue += bytes[step] & 0x7F;
        }
    }
    return byteValue;
}


1243 bytes more | comments? | Printer Friendly Page  Send to a Friend | Score: 0
Posted by jalex on Thursday, August 30, 2007 (20:49:35) (11210 reads)

How to get started with Java

Go to all tips in Murachs Java SE6 book

The chapter 1 of Murach's Java SE 6 excellent book (it is a MUST for all newbees!) is published on our site with written permission of the copyright owner. It was slightly adapted to our site layout. If you want to take a look at PDF version please follow the link here.


TRAINING & REFERENCE

murach's Java SE 6

(Chapter 1)

Thanks for reviewing this chapter from Murach's Java SE 6 To see the expanded table of contents for this book, please go to the Murach web site. From there, you can read more about this book, you can find out about any additional downloads that are available, and you can review other Murach books for professional developers.


java murach book MIKE MURACH & ASSOCIATES, INC.
1-800-221-5528 • (559) 440-9071 • Fax: (559) 440-0963
murachbooks@murach.comwww.murach.com
Copyright © 2007 Mike Murach & Associates. All rights reserved.


Section 1

Essential Java skills

This section gets you started quickly with Java programming. First, chapter 1 shows you how to compile and run Java applications, and chapter 2 introduces you to the basic skills that you need for developing Java applications. When you complete these chapters, you'll be able to write, test, and debug simple applications of your own.

After that, chapter 3 presents the details for working with numeric data. Chapter 4 presents the details for coding control statements. And chapter 5 shows you how to validate the data that's entered by the user. These are the essential skills that you'll use in almost every Java application that you develop. When you finish these chapters, you'll be able to write solid programs of your own. And you'll have the background that you need for learning how to develop object-oriented programs.

1

How to get started with Java

Before you can begin learning the Java language, you need to install Java and learn how to use some tools for working with Java. So that's what you'll learn
in this chapter. Since most Java developers use Windows, the examples in this chapter show how to use Java with Windows. However, the principles
illustrated by these examples apply to all operating systems including Linux, Mac (OS X), and Solaris.

Introduction to Java ...................................................................... 4
Toolkits and platforms ....................................................................... 4
Java compared to C++ ...................................................................... 4
Java compared to C# ........................................................................ 4
Applications, applets, and servlets ....................................................... 6
How Java compiles and interprets code ................................................ 8
How to prepare your system for using Java .................................. 10
How to install the JDK ..........................................................................10
A summary of the directories and files of the JDK ...................................12
How to set the command path ...............................................................14
How to set the class path ..................................................................... 16
How to use TextPad to work with Java ........................................... 18
How to install TextPad ......................................................................... 18
How to use TextPad to save and edit source code ................................... 20
How to use TextPad to compile source code ........................................... 22
How to use TextPad to run an application ............................................... 22
Common error messages and solutions ................................................. 24
How to use the command prompt to work with Java ...................... 26
How to compile source code ................................................................. 26
How to run an application ..................................................................... 26
How to compile source code with a switch .............................................. 28
Essential DOS skills for working with Java ............................................. 30
How to use the documentation for the Java SE API ....................... 32
How to install the API documentation ..................................................... 32
How to navigate the API documentation ................................................. 34
Introduction to Java IDEs ................................................................ 36
The Eclipse IDE for Java ....................................................................... 36
The NetBeans IDE ................................................................................ 38
The BlueJ IDE ...................................................................................... 38
Perspective ....................................................................................... 40


8601 bytes more | comments? | Printer Friendly Page  Send to a Friend | Score: 0
Posted by jalex on Friday, August 17, 2007 (22:05:11) (2943 reads)

Previous 1060 Stories (530 Pages, 2 Per Page) Next

530| 529| 528| 527| 526| 525| 524| 523| 522|
521
| 520| 519| 518| 517| 516| 515| 514| 513| 512| 511| 510| 509| 508| 507| 506| 505| 504| 503| 502| 501| 500| 499| 498| 497| 496| 495| 494| 493| 492| 491| 490| 489| 488| 487| 486| 485| 484| 483| 482| 481| 480| 479| 478| 477| 476| 475| 474| 473| 472| 471| 470| 469| 468| 467| 466| 465| 464| 463| 462| 461| 460| 459| 458| 457| 456| 455| 454| 453| 452| 451| 450| 449| 448| 447| 446| 445| 444| 443| 442| 441| 440| 439| 438| 437| 436| 435| 434| 433| 432| 431| 430| 429| 428| 427| 426| 425| 424| 423| 422| 421| 420| 419| 418| 417| 416| 415| 414| 413| 412| 411| 410| 409| 408| 407| 406| 405| 404| 403| 402| 401| 400| 399| 398| 397| 396| 395| 394| 393| 392| 391| 390| 389| 388| 387| 386| 385| 384| 383| 382| 381| 380| 379| 378| 377| 376| 375| 374| 373| 372| 371| 370| 369| 368| 367| 366| 365| 364| 363| 362| 361| 360| 359| 358| 357| 356| 355| 354| 353| 352| 351| 350| 349| 348| 347| 346| 345| 344| 343| 342| 341| 340| 339| 338| 337| 336| 335| 334| 333| 332| 331| 330| 329| 328| 327| 326| 325| 324| 323| 322| 321| 320| 319| 318| 317| 316| 315| 314| 313| 312| 311| 310| 309| 308| 307| 306| 305| 304| 303| 302| 301| 300| 299| 298| 297| 296| 295| 294| 293| 292| 291| 290| 289| 288| 287| 286| 285| 284| 283| 282| 281| 280| 279| 278| 277| 276| 275| 274| 273| 272| 271| 270| 269| 268| 267| 266| 265| 264| 263| 262| 261| 260| 259| 258| 257| 256| 255| 254| 253| 252| 251| 250| 249| 248| 247| 246| 245| 244| 243| 242| 241| 240| 239| 238| 237| 236| 235| 234| 233| 232| 231| 230| 229| 228| 227| 226| 225| 224| 223| 222| 221| 220| 219| 218| 217| 216| 215| 214| 213| 212| 211| 210| 209| 208| 207| 206| 205| 204| 203| 202| 201| 200| 199| 198| 197| 196| 195| 194| 193| 192| 191| 190| 189| 188| 187| 186| 185| 184| 183| 182| 181| 180| 179| 178| 177| 176| 175| 174| 173| 172| 171| 170| 169| 168| 167| 166| 165| 164| 163| 162| 161| 160| 159| 158| 157| 156| 155| 154| 153| 152| 151| 150| 149| 148| 147| 146| 145| 144| 143| 142| 141| 140| 139| 138| 137| 136| 135| 134| 133| 132| 131| 130| 129| 128| 127| 126| 125| 124| 123| 122| 121| 120| 119| 118| 117| 116| 115| 114| 113| 112| 111| 110| 109| 108| 107| 106| 105| 104| 103| 102| 101| 100| 99| 98| 97| 96| 95| 94| 93| 92| 91| 90| 89| 88| 87| 86| 85| 84| 83| 82| 81| 80| 79| 78| 77| 76| 75| 74| 73| 72| 71| 70| 69| 68| 67| 66| 65| 64| 63| 62| 61| 60| 59| 58| 57| 56| 55| 54| 53| 52| 51| 50| 49| 48| 47| 46| 45| 44| 43| 42| 41| 40| 39| 38| 37| 36| 35| 34| 33| 32| 31| 30| 29| 28| 27| 26| 25| 24| 23| 22| 21| 20| 19| 18| 17| 16| 15| 14| 13| 12| 11| 10| 9| 8| 7| 6| 5| 4| 3| 2| 1|


Home Code Examples Java Forum All Java Tips Books Submit News, Code... Search... Offshore Software Tech Doodling

RSS feed Java FAQ RSS feed Java FAQ News     

    RSS feed Java Forums RSS feed Java Forums

All logos and trademarks in this site are property of their respective owner. The comments are property of their posters, all the rest 1999-2006 by Java FAQs Daily Tips.

Interactive software released under GNU GPL, Code Credits, Privacy Policy