FULL PRODUCT VERSION :
1.7.0_40

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
If you look at the Java source for:

javax.swing.text.View.forwardUpdate(ElementChange, DocumentEvent, Shape, ViewFactory)

at some point it contains a line like:

        index0 = Math.max(index0, 0);
        index1 = Math.max((getViewCount() - 1), 0);
        for (int i = index0; i <= index1; i++) {
   ............................................

The extra line:

        index1 = Math.max((getViewCount() - 1), 0);

was added in one of the Java 1.7 minor bug fix releases and what it does is that when a character is pressed, the event to layout gets forwarded to all line views, inducing a very large performance problem when the document has bidirectional characters in it.

REGRESSION. Last worked in version 7u10

ADDITIONAL REGRESSION INFORMATION:
1.7.0_40

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create a JTextArea with about 500 lines containing bidirectional characters. Edit in it.


REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
None but to overwrite problem method in custom view.