Translate a Java (Spring) App into English

What English changes in messages_en.properties

Coming from French, Spanish or Portuguese, English labels usually come out shorter. Enregistrer les modifications becomes Save changes, so buttons and table headers rarely overflow. Other details, however, need a decision on your part.

• Punctuation: English puts no space before a colon or question mark, so Adresse e-mail : becomes Email address:. If your source uses escaped non-breaking spaces such as \u00a0 or \u202f, check that none survive in front of English punctuation.
• Capitalisation: German or French sources give no guidance on case. Pick either sentence case (Save changes) or title case (Save Changes) for buttons and headings, and apply it everywhere.
• Spelling variant: colour or color, organisation or organization. Java looks up messages_en_US.properties first, then falls back to messages_en.properties for missing keys. A complete _en file, plus a small _en_US file holding only the keys that differ, is enough.
• Dates: a pattern such as date.pattern=dd/MM/yyyy is not translated. For a US audience, you need to change it to MM/dd/yyyy yourself.

Quotes, {0} and plurals: the MessageFormat traps

Spring runs messages that take arguments through MessageFormat. There, a single quote is an escape character and has to be doubled: user.notFound=User {0} doesn''t exist. By default, a message without arguments is not parsed this way, so single quotes stay as they are.

This matters more in English than in many source languages, because of contractions and possessives: {0}''s profile, You don''t have access to {0}. If a quote is left undoubled in a message with an argument, the text after it disappears, or a raw {0} appears on screen.

English has only two plural categories, one and other, but zero is plural: 0 files, whereas French says « 0 fichier ». A construct such as {0,choice,0#no files|1#one file|1<{0} files} must keep its limits and separators; only the text between them changes. Review these strings first, because a badly split branch does not always throw a visible error.

What Manuce returns, and what it does not do

You upload messages.properties (or messages_de.properties, messages_fr.properties, and so on) and get back the same file, in the same format, with English values. It is ready to save as messages_en.properties in your project.

• Indentation, key order, # comments, line endings, encoding and BOM are preserved; only the values change.
• \uXXXX escapes are kept where used, continuation lines ending in \ are respected, and MessageFormat quotes are handled.
• Every translated value is compared with the source. If {0}, {1} or a <b> tag goes missing and the mismatch persists, the source value is kept and the report says so.
• The following are not translated: keys, empty values, URLs, email addresses, numbers, colours, date formats, identifiers and anything you mark as non-translatable.
• A report comes with the file: strings translated, strings left as they were, and why.

Manuce works on message files, not on your code. Text hard-coded in a Thymeleaf template or in a Java exception message is not in these files, so it will not be translated. Pricing is based on the words in the values, excluding keys and tags, so checkout.button.confirm is not counted.

Preparing the files and checking the result

• Collect everything: besides messages.properties, include ValidationMessages.properties if you customise Bean Validation messages. Their {min} and {max} parameters must come through intact.
• Know your default file: if messages.properties is in your source language and there is no _en file, English-speaking users will see that language. Depending on your configuration, Spring may also fall back to the server locale first.
• Encoding: Spring Boot reads message files as UTF-8 by default. If your project still uses ISO-8859-1 with escapes such as \u00fc, the returned file keeps that encoding and those escapes, so there is nothing to convert.
• Testing: run the app with an en locale, via the Accept-Language header or whatever parameter your LocaleResolver expects. Look for unreplaced {0} placeholders and text still in the source language.
• Review: start with choice messages, anything containing '', and the strings flagged in the report.

The free excerpt lets you check the spelling variant and capitalisation style before you pay. For a customer-facing interface, the Professional level is a better fit than Essential, which is meant for internal use.

In practice

1. Take messages.properties (and ValidationMessages.properties, if used) from src/main/resources.
2. Upload the file: you get an instant quote based on the words in the values, plus a free excerpt.
3. Check the spelling variant (colour or color) and capitalisation in the excerpt, then start the translation.
4. Save the returned file as messages_en.properties and read the report.
5. Test the app with an en locale and adjust the date patterns yourself for a US audience.