diff --git a/Makefile b/Makefile
index 6b59ffcbe9..d483a67aed 100644
--- a/Makefile
+++ b/Makefile
@@ -2031,7 +2031,6 @@ gen-pc:
 # ---------------------------------------------------------------------------
 # Jni stuff
 # ---------------------------------------------------------------------------
-
 JAVA_INCLUDE = -I$(JAVA_HOME)/include/ -I$(JAVA_HOME)/include/linux
 ifeq ($(PLATFORM), OS_SOLARIS)
 	ARCH := $(shell isainfo -b)
@@ -2209,6 +2208,13 @@ endif
 	$(MAKE) rocksdbjavastatic_libobjects
 	$(MAKE) rocksdbjavastatic_javalib
 
+ifeq ($(JAR_CMD),)
+ifneq ($(JAVA_HOME),)
+JAR_CMD := $(JAVA_HOME)/bin/jar
+else
+JAR_CMD := jar
+endif
+endif
 rocksdbjavastatic_javalib:
 	cd java; SHA256_CMD='$(SHA256_CMD)' $(MAKE) javalib
 	rm -f java/target/$(ROCKSDBJNILIB)
@@ -2219,11 +2225,11 @@ rocksdbjavastatic_javalib:
 	cd java/target;if [ "$(DEBUG_LEVEL)" == "0" ]; then \
 		strip $(STRIPFLAGS) $(ROCKSDBJNILIB); \
 	fi
-	cd java;jar -cf target/$(ROCKSDB_JAR) HISTORY*.md
-	cd java/target;jar -uf $(ROCKSDB_JAR) $(ROCKSDBJNILIB)
-	cd java/target/classes;jar -uf ../$(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class
-	cd java/target/apidocs;jar -cf ../$(ROCKSDB_JAVADOCS_JAR) *
-	cd java/src/main/java;jar -cf ../../../target/$(ROCKSDB_SOURCES_JAR) org
+	cd java; $(JAR_CMD) -cf target/$(ROCKSDB_JAR) HISTORY*.md
+	cd java/target; $(JAR_CMD) -uf $(ROCKSDB_JAR) $(ROCKSDBJNILIB)
+	cd java/target/classes; $(JAR_CMD) -uf ../$(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class
+	cd java/target/apidocs; $(JAR_CMD) -cf ../$(ROCKSDB_JAVADOCS_JAR) *
+	cd java/src/main/java; $(JAR_CMD) -cf ../../../target/$(ROCKSDB_SOURCES_JAR) org
 	openssl sha1 java/target/$(ROCKSDB_JAR) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAR).sha1
 	openssl sha1 java/target/$(ROCKSDB_JAVADOCS_JAR) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAVADOCS_JAR).sha1
 	openssl sha1 java/target/$(ROCKSDB_SOURCES_JAR) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_SOURCES_JAR).sha1
@@ -2234,15 +2240,15 @@ rocksdbjavastatic_libobjects: $(LIB_OBJECTS)
 
 rocksdbjavastaticrelease: rocksdbjavastatic
 	cd java/crossbuild && (vagrant destroy -f || true) && vagrant up linux32 && vagrant halt linux32 && vagrant up linux64 && vagrant halt linux64 && vagrant up linux64-musl && vagrant halt linux64-musl
-	cd java;jar -cf target/$(ROCKSDB_JAR_ALL) HISTORY*.md
-	cd java/target;jar -uf $(ROCKSDB_JAR_ALL) librocksdbjni-*.so librocksdbjni-*.jnilib
-	cd java/target/classes;jar -uf ../$(ROCKSDB_JAR_ALL) org/rocksdb/*.class org/rocksdb/util/*.class
+	cd java; $(JAR_CMD) -cf target/$(ROCKSDB_JAR_ALL) HISTORY*.md
+	cd java/target; $(JAR_CMD) -uf $(ROCKSDB_JAR_ALL) librocksdbjni-*.so librocksdbjni-*.jnilib
+	cd java/target/classes; $(JAR_CMD) -uf ../$(ROCKSDB_JAR_ALL) org/rocksdb/*.class org/rocksdb/util/*.class
 	openssl sha1 java/target/$(ROCKSDB_JAR_ALL) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAR_ALL).sha1
 
 rocksdbjavastaticreleasedocker: rocksdbjavastatic rocksdbjavastaticdockerx86 rocksdbjavastaticdockerx86_64 rocksdbjavastaticdockerx86musl rocksdbjavastaticdockerx86_64musl
-	cd java;jar -cf target/$(ROCKSDB_JAR_ALL) HISTORY*.md
-	cd java/target;jar -uf $(ROCKSDB_JAR_ALL) librocksdbjni-*.so librocksdbjni-*.jnilib
-	cd java/target/classes;jar -uf ../$(ROCKSDB_JAR_ALL) org/rocksdb/*.class org/rocksdb/util/*.class
+	cd java; $(JAR_CMD) -cf target/$(ROCKSDB_JAR_ALL) HISTORY*.md
+	cd java/target; $(JAR_CMD) -uf $(ROCKSDB_JAR_ALL) librocksdbjni-*.so librocksdbjni-*.jnilib
+	cd java/target/classes; $(JAR_CMD) -uf ../$(ROCKSDB_JAR_ALL) org/rocksdb/*.class org/rocksdb/util/*.class
 	openssl sha1 java/target/$(ROCKSDB_JAR_ALL) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAR_ALL).sha1
 
 rocksdbjavastaticdockerx86:
@@ -2261,21 +2267,29 @@ rocksdbjavastaticdockerarm64v8:
 	mkdir -p java/target
 	docker run --rm --name rocksdb_linux_arm64v8-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:centos7_arm64v8-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
 
+rocksdbjavastaticdockers390x:
+	mkdir -p java/target
+	docker run --rm --name rocksdb_linux_s390x-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:centos7_s390x-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
+
 rocksdbjavastaticdockerx86musl:
 	mkdir -p java/target
-	docker run --rm --name rocksdb_linux_x86-musl-be --platform linux/386 --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_x86-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
+	docker run --rm --name rocksdb_linux_x86-musl-be --platform linux/386 --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_x86-be /rocksdb-host/java/crossbuild/docker-build-linux-alpine.sh
 
 rocksdbjavastaticdockerx86_64musl:
 	mkdir -p java/target
-	docker run --rm --name rocksdb_linux_x64-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_x64-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
+	docker run --rm --name rocksdb_linux_x64-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_x64-be /rocksdb-host/java/crossbuild/docker-build-linux-alpine.sh
 
 rocksdbjavastaticdockerppc64lemusl:
 	mkdir -p java/target
-	docker run --rm --name rocksdb_linux_ppc64le-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_ppc64le-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
+	docker run --rm --name rocksdb_linux_ppc64le-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_ppc64le-be /rocksdb-host/java/crossbuild/docker-build-linux-alpine.sh
 
 rocksdbjavastaticdockerarm64v8musl:
 	mkdir -p java/target
-	docker run --rm --name rocksdb_linux_arm64v8-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_arm64v8-be /rocksdb-host/java/crossbuild/docker-build-linux-centos.sh
+	docker run --rm --name rocksdb_linux_arm64v8-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_arm64v8-be /rocksdb-host/java/crossbuild/docker-build-linux-alpine.sh
+
+rocksdbjavastaticdockers390xmusl:
+	mkdir -p java/target
+	docker run --rm --name rocksdb_linux_s390x-musl-be --attach stdin --attach stdout --attach stderr --volume $(HOME)/.m2:/root/.m2:ro --volume `pwd`:/rocksdb-host:ro --volume /rocksdb-local-build --volume `pwd`/java/target:/rocksdb-java-target --env DEBUG_LEVEL=$(DEBUG_LEVEL) evolvedbinary/rocksjava:alpine3_s390x-be /rocksdb-host/java/crossbuild/docker-build-linux-alpine.sh
 
 rocksdbjavastaticpublish: rocksdbjavastaticrelease rocksdbjavastaticpublishcentral
 
@@ -2297,8 +2311,8 @@ rocksdbjavastaticnexusbundlejar: rocksdbjavageneratepom
 	gpg --yes --output java/target/pom.xml.asc -ab java/pom.xml
 	gpg --yes -ab java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar
 	$(foreach classifier, $(ROCKSDB_JAVA_RELEASE_CLASSIFIERS), gpg --yes -ab java/target/rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar;)
-	jar cvf java/target/nexus-bundle-rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar -C java pom.xml -C java/target pom.xml.sha1 -C java/target pom.xml.asc -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar.sha1 -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar.asc
-	 $(foreach classifier, $(ROCKSDB_JAVA_RELEASE_CLASSIFIERS), jar uf java/target/nexus-bundle-rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar.sha1 -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar.asc;)
+	$(JAR_CMD) cvf java/target/nexus-bundle-rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar -C java pom.xml -C java/target pom.xml.sha1 -C java/target pom.xml.asc -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar.sha1 -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar.asc
+	$(foreach classifier, $(ROCKSDB_JAVA_RELEASE_CLASSIFIERS), $(JAR_CMD) uf java/target/nexus-bundle-rocksdbjni-$(ROCKSDB_JAVA_VERSION).jar -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar.sha1 -C java/target rocksdbjni-$(ROCKSDB_JAVA_VERSION)-$(classifier).jar.asc;)
 
 
 # A version of each $(LIBOBJECTS) compiled with -fPIC
@@ -2313,9 +2327,9 @@ endif
 	$(AM_V_GEN)cd java; SHA256_CMD='$(SHA256_CMD)' $(MAKE) javalib;
 	$(AM_V_at)rm -f ./java/target/$(ROCKSDBJNILIB)
 	$(AM_V_at)$(CXX) $(CXXFLAGS) -I./java/. $(JAVA_INCLUDE) -shared -fPIC -o ./java/target/$(ROCKSDBJNILIB) $(JNI_NATIVE_SOURCES) $(LIB_OBJECTS) $(JAVA_LDFLAGS) $(COVERAGEFLAGS)
-	$(AM_V_at)cd java;jar -cf target/$(ROCKSDB_JAR) HISTORY*.md
-	$(AM_V_at)cd java/target;jar -uf $(ROCKSDB_JAR) $(ROCKSDBJNILIB)
-	$(AM_V_at)cd java/target/classes;jar -uf ../$(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class
+	$(AM_V_at)cd java; $(JAR_CMD) -cf target/$(ROCKSDB_JAR) HISTORY*.md
+	$(AM_V_at)cd java/target; $(JAR_CMD) -uf $(ROCKSDB_JAR) $(ROCKSDBJNILIB)
+	$(AM_V_at)cd java/target/classes; $(JAR_CMD) -uf ../$(ROCKSDB_JAR) org/rocksdb/*.class org/rocksdb/util/*.class
 	$(AM_V_at)openssl sha1 java/target/$(ROCKSDB_JAR) | sed 's/.*= \([0-9a-f]*\)/\1/' > java/target/$(ROCKSDB_JAR).sha1
 
 jclean:
diff --git a/java/Makefile b/java/Makefile
index 9225004268..d5414c678d 100644
--- a/java/Makefile
+++ b/java/Makefile
@@ -237,6 +237,39 @@ JAVA_TESTCLASSPATH = $(JAVA_JUNIT_JAR_PATH):$(JAVA_HAMCREST_JAR_PATH):$(JAVA_MOC
 
 MVN_LOCAL = ~/.m2/repository
 
+# Set the path of the java commands
+ifeq ($(JAVA_CMD),)
+ifneq ($(JAVA_HOME),)
+JAVA_CMD := $(JAVA_HOME)/bin/java
+else
+JAVA_CMD := java
+endif
+endif
+
+ifeq ($(JAVAC_CMD),)
+ifneq ($(JAVA_HOME),)
+JAVAC_CMD := $(JAVA_HOME)/bin/javac
+else
+JAVAC_CMD := javac
+endif
+endif
+
+ifeq ($(JAVAH_CMD),)
+ifneq ($(JAVA_HOME),)
+JAVAH_CMD := $(JAVA_HOME)/bin/javah
+else
+JAVAH_CMD := javah
+endif
+endif
+
+ifeq ($(JAVADOC_CMD),)
+ifneq ($(JAVA_HOME),)
+JAVADOC_CMD := $(JAVA_HOME)/bin/javadoc
+else
+JAVADOC_CMD := javadoc
+endif
+endif
+
 # Set the default JAVA_ARGS to "" for DEBUG_LEVEL=0
 JAVA_ARGS ?=
 
@@ -266,55 +299,55 @@ clean-downloaded:
 
 javadocs: java
 	$(AM_V_GEN)mkdir -p $(JAVADOC)
-	$(AM_V_at)javadoc -d $(JAVADOC) -sourcepath $(MAIN_SRC) -subpackages org
+	$(AM_V_at)$(JAVADOC_CMD) -d $(JAVADOC) -sourcepath $(MAIN_SRC) -subpackages org
 
 javalib: java java_test javadocs
 
 java:
 	$(AM_V_GEN)mkdir -p $(MAIN_CLASSES)
-ifeq ($(shell java -version 2>&1 | grep 1.7.0 > /dev/null; printf $$?), 0)
-	$(AM_V_at)javac $(JAVAC_ARGS) -d $(MAIN_CLASSES)\
+ifeq ($(shell $(JAVAC_CMD) -version 2>&1 | grep 1.7.0 > /dev/null; printf $$?), 0)
+	$(AM_V_at)$(JAVAC_CMD) $(JAVAC_ARGS) -d $(MAIN_CLASSES)\
 		$(MAIN_SRC)/org/rocksdb/util/*.java\
 		$(MAIN_SRC)/org/rocksdb/*.java
 else
-	$(AM_V_at)javac $(JAVAC_ARGS) -h $(NATIVE_INCLUDE) -d $(MAIN_CLASSES)\
+	$(AM_V_at)$(JAVAC_CMD) $(JAVAC_ARGS) -h $(NATIVE_INCLUDE) -d $(MAIN_CLASSES)\
 		$(MAIN_SRC)/org/rocksdb/util/*.java\
 		$(MAIN_SRC)/org/rocksdb/*.java
 endif
 	$(AM_V_at)@cp ../HISTORY.md ./HISTORY-CPP.md
 	$(AM_V_at)@rm -f ./HISTORY-CPP.md
-ifeq ($(shell java -version 2>&1 | grep 1.7.0 > /dev/null; printf $$?), 0)
-	$(AM_V_at)javah -cp $(MAIN_CLASSES) -d $(NATIVE_INCLUDE) -jni $(NATIVE_JAVA_CLASSES)
+ifeq ($(shell $(JAVAH_CMD) -version 2>&1 | grep 1.7.0 > /dev/null; printf $$?), 0)
+	$(AM_V_at)$(JAVAH_CMD) -cp $(MAIN_CLASSES) -d $(NATIVE_INCLUDE) -jni $(NATIVE_JAVA_CLASSES)
 endif
 
 sample: java
 	$(AM_V_GEN)mkdir -p $(SAMPLES_MAIN_CLASSES)
-	$(AM_V_at)javac $(JAVAC_ARGS) -cp $(MAIN_CLASSES) -d $(SAMPLES_MAIN_CLASSES) $(SAMPLES_MAIN_SRC)/RocksDBSample.java
+	$(AM_V_at)$(JAVAC_CMD) $(JAVAC_ARGS) -cp $(MAIN_CLASSES) -d $(SAMPLES_MAIN_CLASSES) $(SAMPLES_MAIN_SRC)/RocksDBSample.java
 	$(AM_V_at)@rm -rf /tmp/rocksdbjni
 	$(AM_V_at)@rm -rf /tmp/rocksdbjni_not_found
-	java $(JAVA_ARGS) -Djava.library.path=target -cp $(MAIN_CLASSES):$(SAMPLES_MAIN_CLASSES) RocksDBSample /tmp/rocksdbjni
+	$(JAVA_CMD) $(JAVA_ARGS) -Djava.library.path=target -cp $(MAIN_CLASSES):$(SAMPLES_MAIN_CLASSES) RocksDBSample /tmp/rocksdbjni
 	$(AM_V_at)@rm -rf /tmp/rocksdbjni
 	$(AM_V_at)@rm -rf /tmp/rocksdbjni_not_found
 
 column_family_sample: java
 	$(AM_V_GEN)mkdir -p $(SAMPLES_MAIN_CLASSES)
-	$(AM_V_at)javac $(JAVAC_ARGS) -cp $(MAIN_CLASSES) -d $(SAMPLES_MAIN_CLASSES) $(SAMPLES_MAIN_SRC)/RocksDBColumnFamilySample.java
+	$(AM_V_at)$(JAVAC_CMD) $(JAVAC_ARGS) -cp $(MAIN_CLASSES) -d $(SAMPLES_MAIN_CLASSES) $(SAMPLES_MAIN_SRC)/RocksDBColumnFamilySample.java
 	$(AM_V_at)@rm -rf /tmp/rocksdbjni
-	java $(JAVA_ARGS) -Djava.library.path=target -cp $(MAIN_CLASSES):$(SAMPLES_MAIN_CLASSES) RocksDBColumnFamilySample /tmp/rocksdbjni
+	$(JAVA_CMD) $(JAVA_ARGS) -Djava.library.path=target -cp $(MAIN_CLASSES):$(SAMPLES_MAIN_CLASSES) RocksDBColumnFamilySample /tmp/rocksdbjni
 	$(AM_V_at)@rm -rf /tmp/rocksdbjni
 
 transaction_sample: java
 	$(AM_V_GEN)mkdir -p $(SAMPLES_MAIN_CLASSES)
-	$(AM_V_at)javac -cp $(MAIN_CLASSES) -d $(SAMPLES_MAIN_CLASSES) $(SAMPLES_MAIN_SRC)/TransactionSample.java
+	$(AM_V_at)$(JAVAC_CMD) -cp $(MAIN_CLASSES) -d $(SAMPLES_MAIN_CLASSES) $(SAMPLES_MAIN_SRC)/TransactionSample.java
 	$(AM_V_at)@rm -rf /tmp/rocksdbjni
-	java -ea -Xcheck:jni -Djava.library.path=target -cp $(MAIN_CLASSES):$(SAMPLES_MAIN_CLASSES) TransactionSample /tmp/rocksdbjni
+	$(JAVA_CMD) -ea -Xcheck:jni -Djava.library.path=target -cp $(MAIN_CLASSES):$(SAMPLES_MAIN_CLASSES) TransactionSample /tmp/rocksdbjni
 	$(AM_V_at)@rm -rf /tmp/rocksdbjni
 
 optimistic_transaction_sample: java
 	$(AM_V_GEN)mkdir -p $(SAMPLES_MAIN_CLASSES)
-	$(AM_V_at)javac -cp $(MAIN_CLASSES) -d $(SAMPLES_MAIN_CLASSES) $(SAMPLES_MAIN_SRC)/OptimisticTransactionSample.java
+	$(AM_V_at)$(JAVAC_CMD) -cp $(MAIN_CLASSES) -d $(SAMPLES_MAIN_CLASSES) $(SAMPLES_MAIN_SRC)/OptimisticTransactionSample.java
 	$(AM_V_at)@rm -rf /tmp/rocksdbjni
-	java -ea -Xcheck:jni -Djava.library.path=target -cp $(MAIN_CLASSES):$(SAMPLES_MAIN_CLASSES) OptimisticTransactionSample /tmp/rocksdbjni
+	$(JAVA_CMD) -ea -Xcheck:jni -Djava.library.path=target -cp $(MAIN_CLASSES):$(SAMPLES_MAIN_CLASSES) OptimisticTransactionSample /tmp/rocksdbjni
 	$(AM_V_at)@rm -rf /tmp/rocksdbjni
 
 $(JAVA_TEST_LIBDIR):
@@ -384,14 +417,14 @@ resolve_test_deps: $(JAVA_JUNIT_JAR_PATH) $(JAVA_HAMCREST_JAR_PATH) $(JAVA_MOCKI
 
 java_test: java resolve_test_deps
 	$(AM_V_GEN)mkdir -p $(TEST_CLASSES)
-ifeq ($(shell java -version 2>&1|grep 1.7.0 >/dev/null; printf $$?),0)
-	$(AM_V_at)javac $(JAVAC_ARGS) -cp $(MAIN_CLASSES):$(JAVA_TESTCLASSPATH) -d $(TEST_CLASSES)\
+ifeq ($(shell $(JAVAC_CMD) -version 2>&1|grep 1.7.0 >/dev/null; printf $$?),0)
+	$(AM_V_at)$(JAVAC_CMD) $(JAVAC_ARGS) -cp $(MAIN_CLASSES):$(JAVA_TESTCLASSPATH) -d $(TEST_CLASSES)\
 		$(TEST_SRC)/org/rocksdb/test/*.java\
 		$(TEST_SRC)/org/rocksdb/util/*.java\
 		$(TEST_SRC)/org/rocksdb/*.java
-	$(AM_V_at)javah -cp $(MAIN_CLASSES):$(TEST_CLASSES) -d $(NATIVE_INCLUDE) -jni $(NATIVE_JAVA_TEST_CLASSES)
+	$(AM_V_at)$(JAVAH_CMD) -cp $(MAIN_CLASSES):$(TEST_CLASSES) -d $(NATIVE_INCLUDE) -jni $(NATIVE_JAVA_TEST_CLASSES)
 else
-	$(AM_V_at)javac $(JAVAC_ARGS) -cp $(MAIN_CLASSES):$(JAVA_TESTCLASSPATH) -h $(NATIVE_INCLUDE) -d $(TEST_CLASSES)\
+	$(AM_V_at)$(JAVAC_CMD) $(JAVAC_ARGS) -cp $(MAIN_CLASSES):$(JAVA_TESTCLASSPATH) -h $(NATIVE_INCLUDE) -d $(TEST_CLASSES)\
 		$(TEST_SRC)/org/rocksdb/test/*.java\
 		$(TEST_SRC)/org/rocksdb/util/*.java\
 		$(TEST_SRC)/org/rocksdb/*.java
@@ -400,8 +433,8 @@ endif
 test: java java_test run_test
 
 run_test:
-	java $(JAVA_ARGS) -Djava.library.path=target -cp "$(MAIN_CLASSES):$(TEST_CLASSES):$(JAVA_TESTCLASSPATH):target/*" org.rocksdb.test.RocksJunitRunner $(JAVA_TESTS)
+	$(JAVA_CMD) $(JAVA_ARGS) -Djava.library.path=target -cp "$(MAIN_CLASSES):$(TEST_CLASSES):$(JAVA_TESTCLASSPATH):target/*" org.rocksdb.test.RocksJunitRunner $(JAVA_TESTS)
 
 db_bench: java
 	$(AM_V_GEN)mkdir -p $(BENCHMARK_MAIN_CLASSES)
-	$(AM_V_at)javac $(JAVAC_ARGS) -cp $(MAIN_CLASSES) -d $(BENCHMARK_MAIN_CLASSES) $(BENCHMARK_MAIN_SRC)/org/rocksdb/benchmark/*.java
+	$(AM_V_at)$(JAVAC_CMD) $(JAVAC_ARGS) -cp $(MAIN_CLASSES) -d $(BENCHMARK_MAIN_CLASSES) $(BENCHMARK_MAIN_SRC)/org/rocksdb/benchmark/*.java
diff --git a/java/crossbuild/docker-build-linux-alpine.sh b/java/crossbuild/docker-build-linux-alpine.sh
index b2f83430b7..e3e852efea 100755
--- a/java/crossbuild/docker-build-linux-alpine.sh
+++ b/java/crossbuild/docker-build-linux-alpine.sh
@@ -12,7 +12,6 @@ cp -r /rocksdb-host/* /rocksdb-local-build
 cd /rocksdb-local-build
 
 make clean-not-downloaded
-PORTABLE=1 make rocksdbjavastatic
-
-cp java/target/librocksdbjni-linux*.so java/target/rocksdbjni-*-linux*.jar java/target/rocksdbjni-*-linux*.jar.sha1x /rocksdb-java-target
+PORTABLE=1 make -j2 rocksdbjavastatic
 
+cp java/target/librocksdbjni-linux*.so java/target/rocksdbjni-*-linux*.jar java/target/rocksdbjni-*-linux*.jar.sha1 /rocksdb-java-target
diff --git a/java/crossbuild/docker-build-linux-centos.sh b/java/crossbuild/docker-build-linux-centos.sh
index 166bc7b6ef..78dbfb6da9 100755
--- a/java/crossbuild/docker-build-linux-centos.sh
+++ b/java/crossbuild/docker-build-linux-centos.sh
@@ -27,7 +27,7 @@ if hash scl 2>/dev/null; then
 	fi
 else
 	make clean-not-downloaded
-        PORTABLE=1 make -j2 rocksdbjavastatic
+	PORTABLE=1 make -j2 rocksdbjavastatic
 fi
 
 cp java/target/librocksdbjni-linux*.so java/target/rocksdbjni-*-linux*.jar java/target/rocksdbjni-*-linux*.jar.sha1 /rocksdb-java-target
diff --git a/port/port_posix.h b/port/port_posix.h
index 2abceef8a7..fdf90c236c 100644
--- a/port/port_posix.h
+++ b/port/port_posix.h
@@ -193,7 +193,7 @@ extern void InitOnce(OnceType* once, void (*initializer)());
 #define ALIGN_AS(n) /*empty*/
 #else
 #if defined(__s390__)
-#if defined(__GNUC__) && __GNUC__ < 6
+#if defined(__GNUC__) && __GNUC__ < 7
 #define CACHE_LINE_SIZE 64U
 #else
 #define CACHE_LINE_SIZE 256U