java - Spring @Value annotation returns null

Spring can not inject @Value to a static field directly.

you can either add inject the value through an annotated setter like this:

private static String keystoreType;

@Value("${client.keystore.type}")
public void setKeystoreType(String keystoreType) {
    SendMessageController.keystoreType = keystoreType;
} 

Or Change :

    @Value("${client.keystore.type}")
    private static String keystoreType;

to :

@Value("${client.keystore.type}")
private String keystoreType;