Update dependencies to use the JGit-internal @Nullable

Update the project-specific Eclipse settings to replace the use of the
org.eclipse.jdt.annotation.Nullable class the new JGit-specific
@Nullable annotation. I verified that Eclipse reports errors when the
return value of a method annotated with
@org.eclipse.jgit.annotations.Nullable is dereferenced without a null
check.

Also remove the Maven and MANIFEST.MF dependencies on
org.eclipse.jdt.annotation.

Eclipse null analysis uses three annotations: @Nullable, @NonNull and
@NonNullByDefault. All three are updated in this patch because it is
invalid to set the Eclipse preferences to empty values. So far only
@Nullable has been introduced in org.eclipse.jgit.annotations.

My personal preference is to follow the advice in Effective Java and
avoid the null-return idiom, and to avoid passing null values in
general. This sets the expectation is that arguments and return types
are assumed non-null unless otherwise documented. If that is the
expectation, then consistent application of @NonNull is redundant and
hurts readability by cluttering the code, obscuring the occasional
@Nullable annotation that really requires attention.

If the JGit community decides there is value in using the @NonNull and
@NonNullByDefault annotations we can add them--this change configures
Eclipse to use them.

Change-Id: I9af1b786d1b44b9b0d9c609480dc842df79bf698
Signed-off-by: Terry Parker <tparker@google.com>

org.eclipse.jgit.archive/.settings/org.eclipse.jdt.core.prefs

@@ -1,9 +1,9 @@
 eclipse.preferences.version=1
 org.eclipse.jdt.core.compiler.annotation.inheritNullAnnotations=enabled
 org.eclipse.jdt.core.compiler.annotation.missingNonNullByDefaultAnnotation=ignore
-org.eclipse.jdt.core.compiler.annotation.nonnull=org.eclipse.jdt.annotation.NonNull
-org.eclipse.jdt.core.compiler.annotation.nonnullbydefault=org.eclipse.jdt.annotation.NonNullByDefault
-org.eclipse.jdt.core.compiler.annotation.nullable=org.eclipse.jdt.annotation.Nullable
+org.eclipse.jdt.core.compiler.annotation.nonnull=org.eclipse.jgit.annotations.NonNull
+org.eclipse.jdt.core.compiler.annotation.nonnullbydefault=org.eclipse.jgit.annotations.NonNullByDefault
+org.eclipse.jdt.core.compiler.annotation.nullable=org.eclipse.jgit.annotations.Nullable
 org.eclipse.jdt.core.compiler.annotation.nullanalysis=enabled
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
 org.eclipse.jdt.core.compiler.codegen.methodParameters=do not generate

org.eclipse.jgit.archive/META-INF/MANIFEST.MF

@@ -24,4 +24,3 @@ Export-Package: org.eclipse.jgit.archive;version="4.2.0";
    org.eclipse.jgit.api,
    org.apache.commons.compress.archivers,
    org.osgi.framework"
-Require-Bundle: org.eclipse.jdt.annotation;bundle-version="[1.1.0,2.0.0)";resolution:=optional

org.eclipse.jgit.pgm/.settings/org.eclipse.jdt.core.prefs

@@ -1,9 +1,9 @@
 eclipse.preferences.version=1
 org.eclipse.jdt.core.compiler.annotation.inheritNullAnnotations=enabled
 org.eclipse.jdt.core.compiler.annotation.missingNonNullByDefaultAnnotation=ignore
-org.eclipse.jdt.core.compiler.annotation.nonnull=org.eclipse.jdt.annotation.NonNull
-org.eclipse.jdt.core.compiler.annotation.nonnullbydefault=org.eclipse.jdt.annotation.NonNullByDefault
-org.eclipse.jdt.core.compiler.annotation.nullable=org.eclipse.jdt.annotation.Nullable
+org.eclipse.jdt.core.compiler.annotation.nonnull=org.eclipse.jgit.annotations.NonNull
+org.eclipse.jdt.core.compiler.annotation.nonnullbydefault=org.eclipse.jgit.annotations.NonNullByDefault
+org.eclipse.jdt.core.compiler.annotation.nullable=org.eclipse.jgit.annotations.Nullable
 org.eclipse.jdt.core.compiler.annotation.nullanalysis=enabled
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
 org.eclipse.jdt.core.compiler.codegen.methodParameters=do not generate

org.eclipse.jgit.pgm/META-INF/MANIFEST.MF

@@ -63,4 +63,3 @@ Export-Package: org.eclipse.jgit.console;version="4.2.0";
    org.kohsuke.args4j"
 Main-Class: org.eclipse.jgit.pgm.Main
 Implementation-Title: JGit Command Line Interface
-Require-Bundle: org.eclipse.jdt.annotation;bundle-version="[1.1.0,2.0.0)";resolution:=optional

org.eclipse.jgit/.settings/org.eclipse.jdt.core.prefs

@@ -1,9 +1,9 @@
 eclipse.preferences.version=1
 org.eclipse.jdt.core.compiler.annotation.inheritNullAnnotations=enabled
 org.eclipse.jdt.core.compiler.annotation.missingNonNullByDefaultAnnotation=ignore
-org.eclipse.jdt.core.compiler.annotation.nonnull=org.eclipse.jdt.annotation.NonNull
-org.eclipse.jdt.core.compiler.annotation.nonnullbydefault=org.eclipse.jdt.annotation.NonNullByDefault
-org.eclipse.jdt.core.compiler.annotation.nullable=org.eclipse.jdt.annotation.Nullable
+org.eclipse.jdt.core.compiler.annotation.nonnull=org.eclipse.jgit.annotations.NonNull
+org.eclipse.jdt.core.compiler.annotation.nonnullbydefault=org.eclipse.jgit.annotations.NonByDefault
+org.eclipse.jdt.core.compiler.annotation.nullable=org.eclipse.jgit.annotations.Nullable
 org.eclipse.jdt.core.compiler.annotation.nullanalysis=enabled
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
 org.eclipse.jdt.core.compiler.codegen.methodParameters=do not generate

org.eclipse.jgit/META-INF/MANIFEST.MF

@@ -154,8 +154,7 @@ Export-Package: org.eclipse.jgit.api;version="4.2.0";
    org.ietf.jgss",
  org.eclipse.jgit.util.io;version="4.2.0"
 Bundle-RequiredExecutionEnvironment: JavaSE-1.7
-Require-Bundle: com.jcraft.jsch;bundle-version="[0.1.37,0.2.0)",
- org.eclipse.jdt.annotation;bundle-version="[1.1.0,2.0.0)";resolution:=optional
+Require-Bundle: com.jcraft.jsch;bundle-version="[0.1.37,0.2.0)"
 Import-Package: com.googlecode.javaewah;version="[0.7.9,0.8.0)",
  javax.crypto,
  javax.net.ssl,

org.eclipse.jgit/pom.xml

@@ -88,12 +88,6 @@
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-api</artifactId>
     </dependency>
-
-	<dependency>
-	    <groupId>org.eclipse.jdt</groupId>
-	    <artifactId>org.eclipse.jdt.annotation</artifactId>
-	    <version>1.1.0</version>
-	</dependency>
   </dependencies>
 
   <build>