diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2d286cc75..ffa231776 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -560,6 +560,10 @@ if(UNIX AND NOT APPLE)
   set(OS_NAME "linux") # sorry BSD
 endif()
 
+if(OVERRIDE_JDBC_OS_NAME)
+  set(OS_NAME ${OVERRIDE_JDBC_OS_NAME})
+endif()
+
 if(OVERRIDE_JDBC_OS_ARCH)
   set(OS_ARCH ${OVERRIDE_JDBC_OS_ARCH})
 endif()
@@ -579,8 +583,8 @@ add_jar(duckdb_jdbc_tests ${JAVA_TEST_FILES} INCLUDE_JARS duckdb_jdbc_nolib)
 
 # main shared lib compilation
 
-if(MSVC)
-  list(APPEND DUCKDB_INCLUDE_DIRS src/windows)
+if(MSVC OR ZOS)
+  list(APPEND DUCKDB_INCLUDE_DIRS src/stubs)
   list(APPEND DUCKDB_SRC_FILES duckdb_java.def)
 else()
   list(APPEND DUCKDB_SRC_FILES ${JEMALLOC_SRC_FILES})
@@ -606,7 +610,7 @@ target_include_directories(duckdb_java PRIVATE
   ${JAVA_INCLUDE_PATH2}
   ${DUCKDB_INCLUDE_DIRS})
 
-if (NOT MSVC)
+if (NOT MSVC AND NOT ZOS)
   target_include_directories(duckdb_java PRIVATE
     ${JEMALLOC_INCLUDE_DIRS})
 endif()
@@ -637,7 +641,7 @@ target_compile_definitions(duckdb_java PRIVATE
   -DDUCKDB_EXTENSION_AUTOLOAD_DEFAULT
   -DDUCKDB_EXTENSION_AUTOINSTALL_DEFAULT)
 
-if(NOT MSVC)
+if(NOT MSVC AND NOT ZOS)
   target_compile_definitions(duckdb_java PRIVATE
     -DDUCKDB_EXTENSION_JEMALLOC_LINKED)
 endif()
diff --git a/CMakeLists.txt.in b/CMakeLists.txt.in
index 3d6f041d6..8633e01be 100644
--- a/CMakeLists.txt.in
+++ b/CMakeLists.txt.in
@@ -78,6 +78,10 @@ if(UNIX AND NOT APPLE)
   set(OS_NAME "linux") # sorry BSD
 endif()
 
+if(OVERRIDE_JDBC_OS_NAME)
+  set(OS_NAME ${OVERRIDE_JDBC_OS_NAME})
+endif()
+
 if(OVERRIDE_JDBC_OS_ARCH)
   set(OS_ARCH ${OVERRIDE_JDBC_OS_ARCH})
 endif()
@@ -97,8 +101,8 @@ add_jar(duckdb_jdbc_tests ${JAVA_TEST_FILES} INCLUDE_JARS duckdb_jdbc_nolib)
 
 # main shared lib compilation
 
-if(MSVC)
-  list(APPEND DUCKDB_INCLUDE_DIRS src/windows)
+if(MSVC OR ZOS)
+  list(APPEND DUCKDB_INCLUDE_DIRS src/stubs)
   list(APPEND DUCKDB_SRC_FILES duckdb_java.def)
 else()
   list(APPEND DUCKDB_SRC_FILES ${JEMALLOC_SRC_FILES})
@@ -124,7 +128,7 @@ target_include_directories(duckdb_java PRIVATE
   ${JAVA_INCLUDE_PATH2}
   ${DUCKDB_INCLUDE_DIRS})
 
-if (NOT MSVC)
+if (NOT MSVC AND NOT ZOS)
   target_include_directories(duckdb_java PRIVATE
     ${JEMALLOC_INCLUDE_DIRS})
 endif()
@@ -155,7 +159,7 @@ target_compile_definitions(duckdb_java PRIVATE
   -DDUCKDB_EXTENSION_AUTOLOAD_DEFAULT
   -DDUCKDB_EXTENSION_AUTOINSTALL_DEFAULT)
 
-if(NOT MSVC)
+if(NOT MSVC AND NOT ZOS)
   target_compile_definitions(duckdb_java PRIVATE
     -DDUCKDB_EXTENSION_JEMALLOC_LINKED)
 endif()
diff --git a/Makefile b/Makefile
index dc269ba25..96e3a8e09 100644
--- a/Makefile
+++ b/Makefile
@@ -12,9 +12,14 @@ else
 	JARS=build/release
 endif
 
-ARCH_OVERRIDE=
+OS_NAME_OVERRIDE=
+ifneq ($(OVERRIDE_JDBC_OS_NAME),)
+	OS_NAME_OVERRIDE=-DOVERRIDE_JDBC_OS_NAME=$(OVERRIDE_JDBC_OS_NAME)
+endif
+
+OS_ARCH_OVERRIDE=
 ifneq ($(OVERRIDE_JDBC_OS_ARCH),)
-	ARCH_OVERRIDE=-DOVERRIDE_JDBC_OS_ARCH=$(OVERRIDE_JDBC_OS_ARCH)
+	OS_ARCH_OVERRIDE=-DOVERRIDE_JDBC_OS_ARCH=$(OVERRIDE_JDBC_OS_ARCH)
 endif
 
 
@@ -33,15 +38,15 @@ test:
 
 debug:
 	mkdir -p build/debug
-	cd build/debug && cmake -DCMAKE_BUILD_TYPE=Debug $(GENERATOR) $(ARCH_OVERRIDE) ../.. && cmake --build . --config Debug
+	cd build/debug && cmake -DCMAKE_BUILD_TYPE=Debug $(GENERATOR) $(OS_NAME_OVERRIDE) $(OS_ARCH_OVERRIDE) ../.. && cmake --build . --config Debug
 
 release:
 	mkdir -p build/release
-	cd build/release && cmake -DCMAKE_BUILD_TYPE=Release $(GENERATOR) $(ARCH_OVERRIDE) ../.. && cmake --build . --config Release
+	cd build/release && cmake -DCMAKE_BUILD_TYPE=Release $(GENERATOR) $(OS_NAME_OVERRIDE) $(OS_ARCH_OVERRIDE) ../.. && cmake --build . --config Release
 
 sanitized:
 	mkdir -p build/sanitized
-	cd build/sanitized && cmake -DCMAKE_BUILD_TYPE=Release -DENABLE_ADDRESS_SANITIZER=ON $(GENERATOR) $(ARCH_OVERRIDE) ../.. && cmake --build . --config Release
+	cd build/sanitized && cmake -DCMAKE_BUILD_TYPE=Release -DENABLE_ADDRESS_SANITIZER=ON $(GENERATOR) $(OS_NAME_OVERRIDE) $(OS_ARCH_OVERRIDE) ../.. && cmake --build . --config Release
 
 format:
 	python3 scripts/format.py
diff --git a/src/main/java/org/duckdb/DuckDBNative.java b/src/main/java/org/duckdb/DuckDBNative.java
index 9570c2c4d..2267bae40 100644
--- a/src/main/java/org/duckdb/DuckDBNative.java
+++ b/src/main/java/org/duckdb/DuckDBNative.java
@@ -72,7 +72,7 @@ private static String cpuArch() {
         case "arm64":
             return ARCH_AARCH64;
         default:
-            throw new IllegalStateException("Unsupported system architecture: '" + prop + "'");
+            return prop.replaceAll("[^a-z0-9_\\-.]", "");
         }
     }
 
@@ -85,7 +85,7 @@ static String osName() {
         } else if (prop.startsWith("linux")) {
             return OS_LINUX;
         } else {
-            throw new IllegalStateException("Unsupported OS: '" + prop + "'");
+            return prop.replaceAll("[^a-z0-9_\\-.]", "");
         }
     }
 
@@ -116,6 +116,8 @@ private static void unpackAndLoad(URL nativeLibRes) throws IOException {
             Files.copy(is, tmpFile, REPLACE_EXISTING);
         }
         tmpFile.toFile().deleteOnExit();
+        // Harmless on the officially supported platforms but required on some other.
+        tmpFile.toFile().setExecutable(true);
         System.load(tmpFile.toAbsolutePath().toString());
     }
 
diff --git a/src/windows/jemalloc_extension.hpp b/src/stubs/jemalloc_extension.hpp
similarity index 100%
rename from src/windows/jemalloc_extension.hpp
rename to src/stubs/jemalloc_extension.hpp