How do I modify Eclipse code formatting?

When I reformat code with Eclipse, it turns method headers like this:

public void myMethod(String param) {

into method headers like this:

public void myMethod(
                     String param) {

When I was brought on here I'd never used Eclipse before, and I imported project settings provided by someone else. I have seen that on small new projects I've worked on Eclipse does not do this, so it must be in the settings I've imported. But I've gone through every panel I can find, as well as every hidden file I can find in the workspace, and I can't figure out what is causing this.

How do I turn it off? I don't want a newline before parameters in my method signatures, and I can't imagine why anyone would!

Have a look at Window>Preferences>Java>Code Style>Formatter.

There you can configure almost everything. Your case is found at

Line Wrapping>Method Declarations>Parameters.

In my version of Eclipse, I found the option under Window->Preferences->Java->Code Style->Formatter, then clicked the Edit.. button.

In the new window, go to the Line Wrapping tab and find Method Declarations. You want to change the Line wrapping policy. The Force split check box seems to do the same.