Guice default value for @Named

Question

I am reading the properties from a conf file using Guice

@Inject
@Named("test.var1")
private int var1 = 2;

Here, the value of test.var1 in the conf file is being injected to var1 successfully. If this property in missing in the file, i want it to be set to 2 by default. But, when this property "test.var1" is missing in the property file, i am getting a compilation error.

Explicit bindings are required and java.lang.Integer annotated with @com.google.inject.name.Named(value=test.var1) is not explicitly bound.
  while locating java.lang.Integer annotated with @com.google.inject.name.Named(value=test.var1)
    for parameter 6 at test1.TestParser.<init>(TestParser.java:62)
  at test1.CarbonServerModule.configure(CarbonServerModule.java:41)

1 error
    at com.google.inject.internal.Errors.throwCreationExceptionIfErrorsExist(Errors.java:435)
    at com.google.inject.internal.InternalInjectorCreator.initializeStatically(InternalInjectorCreator.java:154)
    at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:106)
    at com.google.inject.Guice.createInjector(Guice.java:95)
    at com.google.inject.Guice.createInjector(Guice.java:72)
    at test1.Main.<init>(Main.java:198)
    at test1.Main.main(Main.java:244)

Can someone plz help me with what i am trying to do here?

score 0 · Answer 1 · answered Apr 04 '17 at 07:45

As the error message says, you have configured Guice to require explicit bindings, hence it fails if a known binding is not explicitly declared. Removing that requirement (i.e. allowing implicit bindings) and/or marking the @Inject annotation optional should be sufficient.

Guice default value for @Named

1 Answers1