Bazel@HEAD supports Java 9.

The current code has one single issue with Java 9 compliance: the usage
of javax.xml.bind.DatatypeConverter class for printHexBinary() method.
This class is not available on Java 9. One alternative is to use guava
library. Something similar was done here: [1]. But unlike the case with
checkstyle library, JGit currently doesn't use guava. Instead, we add
java.xml.bind module with --add-modules compiler option.

To build (or test) with Java 9, build custom bazel version and issue:

  $ bazel --host_javabase=/usr/lib64/jvm/java-9-openjdk build \
    --javacopt='--release 9' \
    --java_toolchain=@bazel_tools//tools/jdk:toolchain_jdk9 :all

The Java 9 support is backwards compatible.

* [1] https://github.com/checkstyle/checkstyle/issues/5027

Change-Id: I2c5203fc4e65885ce7b210f824fda85ba6d6c51d
Signed-off-by: David Ostrovsky <david@ostrovsky.org>

com.jcraft.jsch requires com.jcraft.jzlib to provide optional zlib
packet compression support. Add this library so that jgit can handle
packet compression.

CQ: 15292
Bug: 529129
Change-Id: I0297bd0488753547a5f5d47dbf0db508a79dd265
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

Generating the src list with an unrestricted wildcard causes all
files in the source tree to be included. This results in junk files
such as .orig (generated during merge conflict resolution) to be
included, which causes in a build error:

  in srcs attribute of java_library rule //org.eclipse.jgit:jgit:
  file '//org.eclipse.jgit:src/org/eclipse/jgit/gitrepo/RepoCommand.java.orig'
  is misplaced here (expected .java, .srcjar or .properties).

Modify the globs to only include Java source files.

Change-Id: Iaef3db33ac71d71047cd28acb0378e15cb09ece9
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

This provides a place to declare visibility restrictions and
transitive dependencies for each library.

Other targets should only declare dependencies on what they directly
use, making dependencies easier to maintain.

Trim the dependencies of org.eclipse.jgit:jgit to follow that rule.
It declares dependencies on Apache httpcomponents and the servlet
API but doesn't use them.

Tested:
* 'bazel build //...' succeeds
* applying the change https://gerrit-review.googlesource.com/90843
  to a copy of Gerrit, following the instructions there, and running
  'bazel test //...' in that copy of Gerrit still succeeds

Change-Id: I3ab958ce8b3227019cdbe4cc81e0f042e1541034

Without this, using bazel 0.4.4 to build fails:

 ERROR: jgit/org.eclipse.jgit/BUILD:29:1: Java compilation in rule '//org.eclipse.jgit:insecure_cipher_factory' failed: Worker process sent response with exit code: 1.
 jgit/src/org/eclipse/jgit/transport/InsecureCipherFactory.java:63: error: [InsecureCryptoUsage] Insecure usage of a crypto API: the transformation is not a compile-time constant expression.
                return Cipher.getInstance(algo);
                                         ^
    (see http://errorprone.info/bugpattern/InsecureCryptoUsage)

Change-Id: I7f9a3a5117e42cb68544674f5312df0368aa3674

Change-Id: I934114315d2c7cab917f1011b8e55c52367d429f
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

The initial implementation only builds the packages consumed by
Gerrit Code Review.

Test build and execution is not implemented.

We prefer to consume maven_jar custom rule from bazlets repository,
for the same reasons as in the Gerrit project:

* Caching artifacts across different clones and projects
* Exposing source classifiers and neverlink artifact

TEST PLAN:

  $ bazel build :all
  $ unzip -t bazel-genfiles/all.zip
  Archive: bazel-genfiles/all.zip
    testing: libjgit-archive.jar      OK
    testing: libjgit-servlet.jar      OK
    testing: libjgit.jar              OK
    testing: libjunit.jar             OK
  No errors detected in compressed data of bazel-genfiles/all.zip.

Change-Id: Ia837ce95d9829fe2515f37b7a04a71a4598672a0
Signed-off-by: David Ostrovsky <david@ostrovsky.org>
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>