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Prefixing with your module's id

Typically they keys you define in a module's messages.properties file should start with your module's id, and any keys that do not start with your module's id will have it prepended.

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title = My Module  # will be converted to mymodule.title = My Module

Starting in OpenMRS 1.9.3 you are allowed to override this behavior, and let your module define message keys outside of its namespace. To do this, you need to include an a special entry in the properties file like:

openmrs.property.ALLOW_KEYS_OUTSIDE_OF_MODULE_NAMESPACE = true

mymodule.title = My Module's Title  # explicitly inside mymodule namespace
othermodule.othercode = Some Other Value  # defines a code in another module's namespace

Example

The main english file should be named messages.properties.  Each other language will be messages_fr.properties (for frenchFrench)

Example:

messages.properties:

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Now in your jsp files you can use <spring:message code="mymodule.doSomething"/> and it will be translated when the user chooses to use the French locale.

What if I don't know another language?

Most developers only know a single language.  It is acceptable to only fill out the english messages.properties file and wait for another language speaker to help you out.