Debugging: Watches Window

The Watches window lists all variables and expressions that you have specified to watch while debugging. By default, the Watches window opens automatically whenever you start a debugging session. You can open the Watches window by choosing Window > Debugging > Watches.

If you open the Watches window when a debugging session is running, it closes automatically when you end the debugging session. If you open the window when no debugging session is running, it stays open until you close it.

The information given for each watch includes the variable or expression name, type, and value. If the variable has a control to its left, you can click the control to expand or collapse the object. If the object type is displayed in blue underlined text, clicking the text jumps to the object type in the source code. You can click in the Value cell to edit the value directly in the Watches window.

When you add a new variable or expression to the Watches window, the value of the variable or expression is immediately evaluated and displayed. The value of a watch is based on the current context. As you move through your program code, the Watches window is updated to show the value of the watch for that context.

In some cases, the debugger assigns a pound sign (#) and a number as the variable's value. This number is a unique identifier of the given instance. You can use this identifier to determine if a variable points to the same or to a different instance. You cannot edit this value.

Icons

The Watches window displays the following thread icons:

Element Description

Watch icon

Watch object

Fixed Watch icon

Fixed watch object

Static Field icon

Container for a superclass

Static Field icon

Static field of an object

Non-Static Field icon

Non-static field of an object

Actions

The Watches window has the following commands in the context menus:

Element Description

Create Fixed Watch

Enables you to create a fixed watch for the object.

New Watch

Enables you to create a new watch.
Delete Removes the selected object from the Watches window.

Delete All

Removes all objects from the Watches window.

Customize

Opens a dialog box in which you can modify the watch expression.
List Options Enables you to customize the display of the Watches window, including adding and removing columns of information, reordering the columns, and sorting the columns.

Properties

To see all the properties for a watch right-click the node for the watch and choose Properties. By default, all properties are also displayed directly in the Watches window, except for the toString() property.


Related Topics

Developing Applications with NetBeans IDE,

Developing Applications with NetBeans IDE,

Developing Applications with NetBeans IDE,

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