SECTION 2 Editor Insights

Tip 9: Compare Two Files Line by Line (Diff)

In version-controlled files you will notice marks in three colors: Deleted, added, and modified lines are highlighted in red, green, and blue, respectively.

Figure 4 shows the color coding in context. The color-coded bars along the editor’s left edge allow you to track differences between your local copy and the last repository version. Navigate quickly to modified lines by clicking the corresponding marks in the error stripe to the right.

FIGURE 4: Marks representing removed lines, added lines, and modified lines

Click the vertical bars along the left edge for a pop up with inline version control actions (see Figure 5).

FIGURE 5: Click the bars to access inline version control actions

The built-in visual Diff Viewer highlights differences between two files (or two revisions of one file) side by side, line by line. Again, you can tell what type of change occurred by the color of the line. The Modern Diff Viewer in Figure 6 visualizes changes in a very intuitive way.

FIGURE 6: Differences between two files

You can even compare two files that are not under version control: The Diff Viewer works on any pair of local files in the Projects, Files, and Favorites windows.

1. Select two similar files in the Projects (or Files or Favorites) window. Click with the Ctrl key (Mac: Command key) pressed to select the second file.

2. Right-click one of the highlighted files, and select Tools > Diff from the context menu. This menu item appears only when two files are selected.

3. The graphical Diff Viewer appears and gives you a detailed overview of all differences.

See also Tip 10, Roll Back Changes in Files Not Under Version Control (Local History), and Tip 11, Restore Deleted Files Not Under Version Control (Local History).

To get an overview of all exit points of a nonvoid method, place the caret on the return type in the method declaration. The editor will highlight all lines containing return statements with a tan background color.

Have a look at the error stripe at the right side of Figure 8: It displays a tan mark for each exit point. Click the marks to jump to the next exit point and place the caret in that line.

FIGURE 8: Highlighted exit points

Tip Source

http://netbeans.dzone.com/news/10-handy-editor-shortcuts-netbeans-ide-60

Tip 13: Find Out Expected Method Parameters

When you need to know the arguments of a method call, press Alt-P (Mac: Command-P). A quick cheat-sheet pops up listing all possible sets of arguments for the method you are calling (see Figure 9).

FIGURE 9: Possible arguments

http://www.antonioshome.net/blog/pivot/entry.php?id=12

You thought you were accessing an initialized field. The compiler thought you were accessing a local variable of the same name. The compiler has the last word, and you are left with an inexplicable NullPointerException. Your code is suffering from an acute case of DWIMNWIS (“Do what I mean, not what I say”).

The parser cannot guess what you really mean, but at least it can communicate what it thinks you mean. Syntactic and semantic code highlighting gives you feedback about how the parser interprets a piece of code in this context. If the interpretation is not what you expected, the bug probably starts here.

Here some examples of the colors used in Java code and what they mean:

Colors and Styles	Interpretation
Green	Class fields
Blue	Reserved Java keywords and some literals (true, false)
Orange	Strings and character literals
Orange bold	Escape sequences (such as " ") inside string literals
Bold italics	Static method declarations; enum
	Parse errors
	Unused variables
Strikethrough	Deprecated variables or methods
Orange background	Search results
Yellow background	Matching braces, matching tags
Tan background	Highlighted occurrences
// Gray	Comment, Javadoc

Choose Options > Fonts & Colors from the menu to configure colors and text styles using the Options window shown in Figure 10. Use the drop-down menu to customize general colorings for all languages, or colorings for only particular languages, such as Java, JavaScript, HTML, CSS, DTD, Ruby, or C/C++ (and many more). The list of semantic categories that you can highlight depends on the language you have selected.

FIGURE 10: Options window

Tip 15: Mark Occurrences of Identifiers

Place the caret inside an identifier. The editor will highlight all occurrences of this identifier in the class.

Have a look at the error stripe at the right side of Figure 11: It displays a tan mark for each occurrence. Click the marks to jump to the next occurrence.

FIGURE 11: Placing the caret inside an identifier