10 things all JAVA developers should know!!

Since JAVA (I know it's not an acronym, but it stands out like that) was officially introduced in 1995, it has changed the way most of us look at the Operating System. Bill Gate (how ironic) once said that it was not about the hardware but the software which will be the future. A decade or more later, the fifth employee of SUN, John Gage said "The Network is the Computer". Fast-forwarding to the 21st century and John seemed to be right. Anyway, JAVA was built not to depend on an Operating System and deployed through the network. JAVA through its applet technology gave birth to Rich Network Application aka Rich Internet Application (RIA). JAVA is not perfect; or we would not have various releases and more on the way, but JAVA has given birth to a wide range of programming language (just Google it to find out more).

Without further ado, I am going to get back to subject. This is a brief article on what I believe that every Java developers should know regardless of their experience. I do not personally believe that someone with 5 years experience is not as good as someone with 10 years experience. We all develop our own methods of working but as a developer you need to stay abreast of your technology. So, here are my top 10 not in order of importance (or?):

1. Remember the basic of JAVA language and OOP paradigm.
   Most experience developers seem to forget the theory behind the language. I am not saying that they are not good at their job but can they explain to junior developers why they have used interfaces instead of abstract classes or why implement a pattern over another one? As a programmer, you become very arrogant as you believe that you write the best code but in the real world, people work in teams with different skill set and experiences. It is important that you can backup your actions/ codes. A very simple question such as; when should I use a String object instead of a StringBuilder/ StringBuffer? You might take this question lightly but can you actually tell someone else the difference?
   
   
2. Know your technology stack
   All developers have to know their technology stack. What does it mean? JAVA is not like other languages; JAVA has subsets such J2ME and superset such as Java EE. We have our own area of expertise but it is important to know the differences between the various sets of JAVA. Some basic questions such as the differences between SWING, Applet, Servlets, EJBs and JAVAFX will boost your confidence. Most developers do not know how to tweak the JVM and the differences between the JRE and the SDK environment. Do you know why you need the SDK to be installed to run Tomcat but you only need the JRE to run an application?
   
   
3. Experiment with various Java EE framework
   I am not asking you to be an expert in every single Java EE framework but it will make the difference if you are familiar with Spring and EJB. That should actually be the de facto framework that should be on every developers CV. Developers should know the difference between Java EE 5 (soon 6) and Spring. Hibernate is also brilliant and it's used for data access but all developers should have moved to JPA by now. Hibernate also comply with JPA therefore there is no more excuses.
   
   
4. Know a scripting language
   JAVA can be heavyweight for some simple tasks which can be implemented using a simple dynamic language such as Python, Perl(?) and others. I would also recommend to developers to learn shell scripting on their target OS.
   
   
5. Know how to develop web services
   The network is the computer, therefore it is important to know the different web services framework available. Data are integrated through web services and opening your services to the "cloud". SWING developers will probably not develop web services but I am sure that they will be connecting to data through web services clients. Understanding the difference between the standardised SOAP and non-standardised ReST will help you choose which is best to implement your services.
   
   
6. Know how and when to multithread your application
   I have to put that in there. Developers should know when and why to multithread an application, thread inter-communication and monitoring. All developers, junior or not, should know how to write a multi-threaded application.
   
   
7. Database development using JDBC and JPA
   This should be a development law. All developers should know how to write SQL queries and how to create databases. All enterprise applications store data in some sort of relational database systems and it is therefore imperative that this knowledge should be of second nature. Java EE 5 introduced JPA (JDO was there before) but it is not applicable to all situation. Hence, knowing the difference and when to implement one instead of the other is important.
   
   
8. Know a client side scripting language and what is AJAX
   The network is the computer and Internet is the deployment platform. Java EE and its various framework are server side executiong which can put extra "load" on the server. If you are looking to move a cloud based system where the providers charges you per resources used, it might be wise to move some of the execution to the client side. AJAX has been buzzing the scene for the last 3 years and more. This is not a technology but a new way of doing something that already existed. There are numerous JAVA AJAX framework such as GWT and DWR which makes it easy to develop AJAX based application which are compiled to JavaScript. Developers should also know what is the AJAX theories.
   
   
9. Know your competitors and do not take part on "what is the best IDE" discussion
   JAVA is not the only language that can do what it does. I think that JAVA is more mature and complete as opposed to other languages. Knowing the difference between JAVA and .NET or JAVA and Ruby is a good asset to have. You also need to know when and why to use one instead of the other. Please please please, do not get into "my IDE is better than x because..." discussion as it is good for the JAVA community to have multiple IDEs and framework available to use. Every tools have their place as for example JDeveloper is better than x if you are going to solely develop on an Oracle stack and etc...
   
   
10. Know ANT (MAVEN?), TOMCAT and any other mainstrean application server
    ANT is the de facto build script for JAVA and its IDE-based development. Maven is becoming popular and soon can be as popular as ANT (not sure of its popularity in the financial sector). TOMCAT should be immortalised as the based servlet container that all developers should be familiar with.

Effective Eclipse: II. Shortcut keys

Use your hands to write code

You should try to keep your hands on keyboard. The less you touch the mouse, the more code you can write. I am trying to keep the mouse laying still and control the IDE completely using keyboard. What do you think is faster: pressing ALT + C or right clicking the project, selecting Team -> Commit?

It is said, that if a function does not have a key binding, it is useless. Below you will find a set of essential keyboard shortcuts that I love. These shortcuts are set up by default, they should all work.

CTRL + D

Delete row. Try it! You no more need to grab the mouse and select the line, no more Home, Shift + End, Delete. Quick and clean.

ALT + Up/Down Arrow

Move the row (or the entire selection) up or down. Very useful when rearranging code. You can even select more rows and move them all. Notice, that it will be always correctly indented.

ALT + Left/Right Arrow

Move to the last location you edited. Imagine you just created a class Foo, and now you are working on a class Boo. Now, if you need to look at the Foo class, just press Alt+Left Arrow. Alt+Right Arrow brings you back to Boo.

CTRL+SHIFT+O

Organize imports. What happens when you first use a class you have not yet imported? You will see an error. But when you press this magical combination, all your missing classes will be imported, and the unused imports will vanish.

CTRL+1

Probably the most useful one. It activates the quick fix. Imagine you create a class, which implements some interface. You will get an error, because the inherited methods are not yet implemented. While you are on line where the error occurs, press this combination to activate the quick fix. Now, select the "Add unimplemented methods" option. You can use the quick fix at every error you ever receive.

Quick fix comes handy in other situations too. My favorite is the "Split variable declaration". Sometimes I need to broaden the scope of a variable. I activate the quick fix, split declaration, and use alt + arrow to put it where it belongs. You can find even more usages: Convert local variable to field, rename in file, Inline local variable..


You could use the "Split variable declaration" on the bar variable, and then move it with Alt+Arrows above the try block..


Or you could use the "Add unimplemented methods" fix here.

The best thing you can do if you see an error is to use the quick fix.

CTRL+SHIFT+T

Open Type. Imagine, that you need to have a look at the Foo class. But, where is the Foo class? Is it in the Boo project and in the foo.bar package? Or somewhere else? With this shortcut, you don't need to know. Just press it, type Foo and you are in.

CTRL+E

Shows you a list of all open editors.

CTRL+F6

Use to move between open editors. This is an slower alternative to Ctrl + E. Comes handy in a situation when you want to periodically switch between two editors, something, what is nearly impossible with Ctrl+E as it sorts entries quite randomly. Or you might just use Alt+Arrows..

CTRL+F7

Move between views. When in editor, press Ctrl+F7 to switch to the Package Explorer, or hold Ctrl and press F7 multiple times to switch to other views.

CTRL+F8

Move between perspectives. The same as previous.

CTRL + F11

Runs the application. What gets launched depends on your settings. It will either launch the last launched class (my preffered way) or it will launch currently selected resource (the default way). If you want to change its behavior read the previous post.

CTL + N

Open new type wizard. This is not very quick because you have to select the wizard type (weather you want to create new class, jsp, xml or something else) in the next step. Much faster way would be if you could just hit the shortcut and invoke the particular wizard. It is possible, just keep reading..

CTRL + M

Maximize or umaximize current tab.

CTRL + I

Corrects indentation.

CTRL + SHIFT + F

Formats code. You can make a beautiful looking code out of a mess with this. It requires a bit of setup, but it is well worth it. You can find its settings under Window->Preferences->Java->Code style->Formatter

CTRL + J

Incremental search. Similar to the search in firefox. It shows you results as you type. Don't be surprised, if you hit this combination, nothing happens - at the first glance. Just start typing and eclipse will move your cursor to the first ocurence.

CTRL + SHIFT + L

Shows you a list of your currently defined shortcut keys.

I don't like your shortcuts

Such is life nowadays. Remember, you can always change those bindings to match your preferences. Open Windows->Preferences->General->Keys. Now you can use the filter to find your shortcut and change its binding.

The real fun begins when you cannot find the command you are looking for. The key here, is to have the "Include unbounds commands" checkbox checked. It will show you all commands, even those, which have no keys bound.



While you are here, I recommend to add the following bindings:

CTRL+SHIFT+G

Bind this to "Generate getters and setters". This is a "must have".

ALT+C

Bind this to SVN/CVS "Commit".

ALT+U

Bind this to SVN/CVS "Update".

Now, type "new" (without quotes) in the filter text. You should see a list of all new type wizards. Choose the most frequently used and assign them a shortcut. For example, the most used wizard for me is the new class wizard. Thus I assigned it the CTRL+SHIFT+N keys.


Let me demonstrate a quick way to create new class now.

Hit CTRL + SHIFT + N (or the combination you assigned in the previous step). This should bring up new class wizard. Type in the name and press ALT+E. You can now select a class which will be a superclass for the newly created class. Hit ALT+A and select all implemented interfaces . Now hit ALT+F and your class will be generated. Eclipse will also provide the default implementation for all abstract and interface methods you inherited.

Did you notice the weird underscores everywhere in the dialog? They give you a hint about the shortcut key. Hit ALT and the underlined letter to press the button, check the checkbox or get focus for a textfield.

Did you notice the underscores?

I think that using shortcut keys is the fastest way to productivity and if not, then at least your wrists will say you a silent thanks. Now, don't wait, go on and assign keys to the features you use most.

One final tip from Andriy:

The problem is that there are so many keyboard shortcuts. I used to keep a printout with all the shortcuts I wanted to use. Finally I wrote an Eclipse plugin MouseFeed, which reminds the keyboard shortcuts for the actions called with mouse. You can even tell it to enforce some shortcuts - the action will run only if called with a keyboard shortcut.

So if you are struggling with yourself, if you want to use shortcuts, but always subconsciously touch the mouse, install the plugin and let it enforce the shortcuts - the mouse will be useless and you will be forced to use keyboard.

What shortcuts do you use?

shortcut key in eclipse

Use your hands to write code


You should try to keep your hands on keyboard. The less you touch the mouse, the more code you can write. I am trying to keep the mouse laying still and control the IDE completely using keyboard. What do you think is faster: pressing ALT + C or right clicking the project, selecting Team -> Commit?

It is said, that if a function does not have a key binding, it is useless. Below you will find a set of essential keyboard shortcuts that I love. These shortcuts are set up by default, they should all work.

CTRL + D

Delete row. Try it! You no more need to grab the mouse and select the line, no more Home, Shift + End, Delete. Quick and Clean.

ALT + Up/Down Arrow

Move the row (or the entire selection) up or down. Very useful when rearranging code.

ALT + Left/Right Arrow

Move to the last location you edited. Imagine you just created a class Foo, and now you are working on a class Boo. Now, if you need to look at the Foo class, just press Alt+Left Arrow. Alt+Right Arrow brings you back to Boo.

CTRL+SHIFT+O

Organize imports. What happens when you first use a class you have not yet imported? You will see an error. But when you press this magical combination, all your missing classes will be imported, and the unused imports will vanish.

CTRL+1

Probably the most useful one. It activates the quick fix. Imagine you create a class, which implements some interface. You will get an error, because the inherited methods are not yet implemented. While you are on line where the error occurs, press this combination to activate the quick fix. Now, select the "Add unimplemented methods" option. You can use the quick fix at every error you ever receive.

Quick fix comes handy in other situations too. My favorite is the "Split variable declaration". Sometimes I need to broaden the scope of a variable. I activate the quick fix, split declaration, and use alt + arrow to put it where it belongs. You can find even more usages: Convert local variable to field, rename in file, Inline local variable..


You could use the "Split variable declaration" on the bar variable, and then move it with Alt+Arrows above the try block..


Or you could use the "Add unimplemented methods" fix here.

The best thing you can do if you see an error is to use the quick fix.

CTRL+SHIFT+T

Open Type. Imagine, that you need to have a look at the Foo class. But, where is the Foo class? Is it in the Boo project and in the foo.bar package? Or somewhere else? With this shortcut, you don't need to know. Just press it, type Foo and you are in.

CTRL+E

Shows you a list of all open editors.

CTRL+F6

Use to move between open editors. This is an slower alternative to Ctrl + E. Comes handy in a situation when you want to periodically switch between two editors, something, what is nearly impossible with Ctrl+E as it sorts entries quite randomly. Or you might just use Alt+Arrows..

CTRL+F7

Move between views. When in editor, press Ctrl+F7 to switch to the Package Explorer, or hold Ctrl and press F7 multiple times to switch to other views.

CTRL + F11

Runs the application. What gets launched depends on your settings. It will either launch the last launched class (my preffered way) or it will launch currently selected resource (the default way). If you want to change its behavior read the previous post.

CTL + N

Open new type wizard. This is not very quick because you have to select the wizard type (weather you want to create new class, jsp, xml or something else) in the next step. Much faster way would be if you could just hit the shortcut and invoke the particular wizard. It is possible, just keep reading..

CTRL + M

Maximize or umaximize current tab.

CTRL + I

Corrects indentation.

CTRL + SHIFT + F

Formats code. You can make a beautiful looking code out of a mess with this. It requires a bit of setup, but it is well worth it. You can find its settings under Window->Preferences->Java->Code style->Formatter

CTRL + J

Incremental search. Similar to the search in firefox. It shows you results as you type. Don't be surprised, if you hit this combination, nothing happens - at the first glance. Just start typing and eclipse will move your cursor to the first ocurence.

CTRL + SHIFT + L

Shows you a list of your currently defined shortcut keys.

I don't like your shortcuts

Such is life nowadays. Remember, you can always change those bindings to match your preferences. Open Windows->Preferences->General->Keys. Now you can use the filter to find your shortcut and change its binding.
The real fun begins when you cannot find the command you are looking for. The key here, is to have the "Include unbounds commands" checkbox checked. It will show you all commands, even those, which have no keys bound.

While you are here, I recommend to add the following bindings:

CTRL+SHIFT+G

Bind this to "Generate getters and setters". This is a "must have".

ALT+C

Bind this to SVN/CVS "Commit".

ALT+U

Bind this to SVN/CVS "Update".

Now, type "new" (without quotes) in the filter text. You should see a list of all new type wizards. Choose the most frequently used and assign them a shortcut. For example, the most used wizard for me is the new class wizard. Thus I assigned it the CTRL+SHIFT+N keys.

Let me demonstrate a quick way to create new class now.


Hit CTRL + SHIFT + N (or the combination you assigned in the previous step). This should bring up new class wizard. Type in the name and press ALT+E. You can now select a class which will be a superclass for the newly created class. Hit ALT+A and select all implemented interfaces . Now hit ALT+F and your class will be generated. Eclipse will also provide the default implementation for all abstract and interface methods you inherited.


Did you notice the weird underscores everywhere in the dialog? They give you a hint about the shortcut key. Hit ALT and the underlined letter to press the button, check the checkbox or get focus for a textfield.


Did you notice the underscores?

I think that using shortcut keys is the fastest way to productivity and if not, then at least your wrists will say you a silent thanks. Now, don't wait, go on and assign keys to the features you use most.

Source: http://tkramar(...)-shortcut-keys_16.html