diff --git a/makefiles/Makefile.java.mk b/makefiles/Makefile.java.mk
index ba04b96397..a1a0932304 100755
--- a/makefiles/Makefile.java.mk
+++ b/makefiles/Makefile.java.mk
@@ -98,10 +98,6 @@ $(GEN_DIR)/ortools/constraint_solver/constraint_solver_java_wrap.cc: \
  -module main \
  -outdir $(GEN_PATH)$Sjava$Scom$Sgoogle$Sortools$Sconstraintsolver \
  $(SRC_DIR)$Sortools$Sconstraint_solver$Sjava$Srouting.i
-	$(SED) -i -e 's/< long long >/< int64 >/g' \
- $(GEN_PATH)$Sortools$Sconstraint_solver$Sconstraint_solver_java_wrap.cc
-	$(SED) -i -e 's/< long long,long long >/< int64, int64 >/g' \
- $(GEN_PATH)$Sortools$Sconstraint_solver$Sconstraint_solver_java_wrap.cc
 
 $(OBJ_DIR)/swig/constraint_solver_java_wrap.$O: \
  $(GEN_DIR)/ortools/constraint_solver/constraint_solver_java_wrap.cc \
@@ -184,8 +180,6 @@ $(GEN_DIR)/ortools/sat/sat_java_wrap.cc: \
  -module main \
  -outdir $(GEN_PATH)$Sjava$Scom$Sgoogle$Sortools$Ssat \
  $(SRC_DIR)$Sortools$Ssat$Sjava$Ssat.i
-	$(SED) -i -e 's/< long long >/< int64 >/g' \
- $(GEN_PATH)$Sortools$Ssat$Ssat_java_wrap.cc
 
 $(OBJ_DIR)/swig/sat_java_wrap.$O: \
  $(GEN_DIR)/ortools/sat/sat_java_wrap.cc \
@@ -206,8 +200,6 @@ $(GEN_DIR)/ortools/util/util_java_wrap.cc: \
  -module main \
  -outdir $(GEN_PATH)$Sjava$Scom$Sgoogle$Sortools$Sutil \
  $(SRC_DIR)$Sortools$Sutil$Sjava$Ssorted_interval_list.i
-	$(SED) -i -e 's/< long long >/< int64 >/g' \
- $(GEN_PATH)$Sortools$Sutil$Sutil_java_wrap.cc
 
 $(OBJ_DIR)/swig/util_java_wrap.$O: \
  $(GEN_DIR)/ortools/util/util_java_wrap.cc \
diff --git a/ortools/algorithms/java/knapsack_solver.i b/ortools/algorithms/java/knapsack_solver.i
index 14950eddcc..3314d16b20 100644
--- a/ortools/algorithms/java/knapsack_solver.i
+++ b/ortools/algorithms/java/knapsack_solver.i
@@ -19,7 +19,6 @@
 // TODO(user): test all lines marked "untested".
 
 %include "enums.swg"
-%include "stdint.i"
 
 %include "ortools/base/base.i"
 %import "ortools/util/java/vector.i"
diff --git a/ortools/base/base.i b/ortools/base/base.i
index 41fe0a9725..2c76df7a7e 100644
--- a/ortools/base/base.i
+++ b/ortools/base/base.i
@@ -72,9 +72,31 @@ COPY_TYPEMAPS(uint64_t, uint64);
 
 #endif // SWIGPYTHON
 
-#if defined(SWIGJAVA) || defined(SWIGCSHARP)
 
-#endif  // defined(SWIGJAVA) || defined(SWIGCSHARP)
+#if defined(SWIGJAVA)
+// swig/java/typenames.i and swig/java/java.swg typemap C++ 'long int' as Java 'int'
+// but in C++ 'int64' aka 'int64_t' is defined as "long int" and we have
+// overload functions int/int64 in routing...
+// So we need to force C++ 'long int' to map to Java 'long' instead of 'int' reusing the
+// typemap for C++ `long long`
+// note: there is no `ulong` in java so we map both on Java `long` type.
+#if defined(SWIGWORDSIZE64)
+%define PRIMITIVE_TYPEMAP(NEW_TYPE, TYPE)
+%clear NEW_TYPE;
+%clear NEW_TYPE *;
+%clear NEW_TYPE &;
+%clear const NEW_TYPE &;
+%apply TYPE { NEW_TYPE };
+%apply TYPE * { NEW_TYPE * };
+%apply TYPE & { NEW_TYPE & };
+%apply const TYPE & { const NEW_TYPE & };
+%enddef // PRIMITIVE_TYPEMAP
+PRIMITIVE_TYPEMAP(long int, long long);
+PRIMITIVE_TYPEMAP(unsigned long int, long long);
+#undef PRIMITIVE_TYPEMAP
+#endif // defined(SWIGWORDSIZE64)
+
+#endif // defined(SWIGJAVA)
 
 // SWIG macros for explicit API declaration.
 // Usage:
diff --git a/ortools/constraint_solver/java/constraint_solver.i b/ortools/constraint_solver/java/constraint_solver.i
index 39fa968354..63949097d5 100644
--- a/ortools/constraint_solver/java/constraint_solver.i
+++ b/ortools/constraint_solver/java/constraint_solver.i
@@ -13,9 +13,9 @@
 
 // TODO(user): Refactor this file to adhere to the SWIG style guide.
 
+
 %include "enumsimple.swg"
 %include "exception.i"
-%include "stdint.i"
 
 %include "ortools/base/base.i"
 %include "ortools/util/java/tuple_set.i"
diff --git a/ortools/sat/java/sat.i b/ortools/sat/java/sat.i
index 94000190e1..c795c5a6ed 100644
--- a/ortools/sat/java/sat.i
+++ b/ortools/sat/java/sat.i
@@ -11,8 +11,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-%include "stdint.i"
-
 %include "ortools/base/base.i"
 
 %include "ortools/util/java/proto.i"
diff --git a/ortools/util/java/vector.i b/ortools/util/java/vector.i
index af79859fcd..a96ad6838c 100644
--- a/ortools/util/java/vector.i
+++ b/ortools/util/java/vector.i
@@ -20,8 +20,6 @@
 //
 // TODO(user): move to base/swig/java.
 
-%include "stdint.i"
-
 %include "ortools/base/base.i"
 
 %{