v3.15 updates

.github/RELEASE_TEMPLATE.md

@@ -25,7 +25,7 @@ conda install -c conda-forge neqsim=<version>
 Requirements:
 
 - Python 3.9 or newer.
-- Java 11 or newer for pip installs.
+- Java 17 or newer for pip installs. Download from [Adoptium](https://adoptium.net/).
 - Conda installs include OpenJDK through conda-forge.
 
 Verify the installed package version without starting the JVM:
@@ -62,6 +62,6 @@ printFrame(natural_gas)
 ## Maintainer Checklist
 
 - Confirm `pyproject.toml` and `conda/meta.yaml` use this version.
-- Confirm bundled JAR files match this version for each supported Java runtime.
+- Confirm the bundled JAR at `src/neqsim/lib/neqsim-<version>.jar` matches this version.
 - Run the relevant tests or packaging checks before publishing.
 - Publish the GitHub release only when ready to trigger the PyPI release workflow.

.github/workflows/runtests.yml

@@ -8,11 +8,37 @@
       - master
 
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+
+      - name: Install uv
+        run: pipx install uv
+
+      - name: Setup Python
+        uses: actions/setup-python@v6
+        with:
+          python-version: "3.13"
+
+      - name: Install dependencies
+        run: uv sync
+
+      - name: Check formatting with black
+        run: uv run black --check --include '\.py$' src/neqsim tests
+
+      - name: Type check with mypy (advisory, non-blocking)
+        continue-on-error: true
+        run: uv run mypy src/neqsim
+
   build:
     strategy:
+      fail-fast: false
       matrix:
-        version: [3.9, 3.12, 3.13]
+        version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
     runs-on: ubuntu-latest
+    # 3.14 is very new; don't fail the whole matrix while the ecosystem catches up.
+    continue-on-error: ${{ matrix.version == '3.14' }}
     steps:
       - uses: actions/checkout@v7
 

CONTRIBUTING.md

@@ -13,10 +13,21 @@ Please note we have a code of conduct, please follow it in all your interactions
    Pull Request would represent. The versioning scheme we use is [SemVer](http://semver.org/).
 4. You may merge the Pull Request in once you have the sign-off of two other developers, or if you do not have permission to do that, you may request the second reviewer to merge it for you.
 
+## Development Checks
+
+Before opening a PR, run the same checks CI runs:
+
+```bash
+uv sync
+uv run black --check --include '\.py$' src/neqsim tests   # required — CI fails on violations
+uv run mypy src/neqsim                                     # advisory — CI reports but does not block
+uv run pytest -p no:faulthandler                            # full test suite
+```
+
 ## Release Process
 
 1. Update the release version in `pyproject.toml` and `conda/meta.yaml`.
-2. Update the bundled NeqSim JAR files under `src/neqsim/lib/` for each supported Java runtime.
+2. Update the bundled NeqSim JAR file at `src/neqsim/lib/neqsim-<version>.jar` (Java 17+ only).
 3. Draft the GitHub release body from `.github/RELEASE_TEMPLATE.md`, keeping the installation and quick-start sections in the release notes.
 4. Use GitHub's generated release notes to include categorized pull requests. The categories are configured in `.github/release.yml`.
 5. Publish the GitHub release only when ready. A published release triggers the PyPI publishing workflow and the Java stub generation workflow.

README.md

@@ -46,7 +46,7 @@ It provides Python toolboxes such as [thermoTools](https://github.com/equinor/ne
 ### Install
 
 <table>
-<tr><td><strong>pip</strong> (requires Java 11+)</td><td><strong>conda</strong> (Java included)</td></tr>
+<tr><td><strong>pip</strong> (requires Java 17+)</td><td><strong>conda</strong> (Java included)</td></tr>
 <tr>
 <td>
 
@@ -65,7 +65,7 @@ conda install -c conda-forge neqsim
 </tr>
 </table>
 
-> **Prerequisites:** Python 3.9+ and Java 11+. The conda package automatically installs OpenJDK — no separate Java setup needed. For pip, install Java from [Adoptium](https://adoptium.net/).
+> **Prerequisites:** Python 3.9+ and Java 17+ (NeqSim 3.15+ requires Java 17 or higher; earlier NeqSim releases required Java 11+). The conda package automatically installs OpenJDK — no separate Java setup needed. For pip, install Java from [Adoptium](https://adoptium.net/).
 
 ### Try it now
 
@@ -246,6 +246,29 @@ Explore ready-to-run examples in the [examples folder](https://github.com/equino
 
 The full list of Python dependencies is on the [dependencies page](https://github.com/equinor/neqsim-python/network/dependencies).
 
+### JVM Startup Control
+
+By default, `import neqsim` starts the JVM immediately. This can be tuned via environment variables:
+
+| Variable | Default | Purpose |
+|----------|---------|---------|
+| `NEQSIM_JVM_AUTOSTART` | `1` | Set to `0`/`false`/`no` to disable automatic JVM startup on import. Call `init_jvm()` explicitly before using `jneqsim`. |
+| `NEQSIM_JVM_ARGS` | *(none)* | Extra JVM startup arguments (space separated), appended after the default `-Xrs`. |
+| `NEQSIM_JVM_MAX_HEAP` | *(none)* | Max JVM heap size, e.g. `2g` — passed as `-Xmx2g`. |
+
+```python
+import os
+os.environ["NEQSIM_JVM_AUTOSTART"] = "0"  # must be set before `import neqsim`
+
+from neqsim.neqsimpython import init_jvm, is_jvm_started
+
+print(is_jvm_started())        # False
+init_jvm(jvm_args=["-Xrs"])     # start explicitly, e.g. with custom args
+print(is_jvm_started())        # True
+```
+
+`init_jvm()` is safe to call multiple times — it is a no-op if the JVM is already running.
+
 ---
 
 ## 🏗️ Contributing

conda/meta.yaml

@@ -24,7 +24,7 @@ requirements:
     - jpype1 >=1.7.0,<2.0.0
     - numpy >1.25.2
     - pandas >=2.0.3,<3.0.0
-    - openjdk >=11
+    - openjdk >=17
 
 test:
   imports:

docs/release-notes/v3.15.0.md

@@ -7,6 +7,9 @@ NeqSim Python is the Python interface to the NeqSim engine for thermodynamic cal
 - Aligns Python package metadata and the conda recipe with version 3.15.0.
 - Improves editor code completion by shipping typing stubs for `jneqsim` through the `neqsim` package export.
 - Ensures `jneqsim` and `jpype` stub packages are included in built source distributions.
+- Adds JVM startup control: set `NEQSIM_JVM_AUTOSTART=0` to defer JVM startup and call the new `init_jvm()` explicitly, with `NEQSIM_JVM_ARGS`/`NEQSIM_JVM_MAX_HEAP` to customize startup arguments and heap size. See the [JVM Startup Control](https://github.com/equinor/neqsim-python#jvm-startup-control) section of the README.
+- Removes the unused bundled Java 8 JAR (~52 MB) and flattens the remaining JAR to `src/neqsim/lib/neqsim-3.15.0.jar` (no more `java11/` subfolder), reducing the installed package size.
+- **Raises the minimum Java version from 11+ to 17+.** Starting with NeqSim 3.15, importing `neqsim` with an older JVM raises a clear `NeqSimJVMError` telling you to upgrade. Download Java 17+ from [Adoptium](https://adoptium.net/).
 
 ## Install
 
@@ -25,7 +28,7 @@ conda install -c conda-forge neqsim=3.15.0
 Requirements:
 
 - Python 3.9 or newer.
-- Java 11 or newer for pip installs.
+- Java 17 or newer for pip installs (raised from Java 11+ in earlier NeqSim releases). Download from [Adoptium](https://adoptium.net/).
 - Conda installs include OpenJDK through conda-forge.
 
 Verify the installed package version without starting the JVM:

environment.yml

@@ -8,7 +8,7 @@ channels:
   - defaults
 dependencies:
   - python>=3.9
-  - openjdk>=11
+  - openjdk>=17
   - jpype1>=1.7.0,<2.0.0
   - numpy>1.25.2
   - pandas>=2.0.3,<3.0.0

pyproject.toml

@@ -39,6 +39,7 @@ dev = [
     "pytest>=8.0.0,<9",
     "pre-commit>=3.6.0,<4",
     "stubgenj>=0.2.12,<0.3",
+    "mypy>=1.10,<3",
 ]
 
 [tool.uv]

src/jneqsim-stubs/__init__.pyi

@@ -1,5 +1,5 @@
-
 import sys
+
 if sys.version_info >= (3, 8):
     from typing import Protocol
 else:
@@ -23,7 +23,6 @@ import jneqsim.thermodynamicoperations
 import jneqsim.util
 import typing
 
-
 class __module_protocol__(Protocol):
     # A module protocol which reflects the result of ``jp.JPackage("neqsim")``.
 

src/jneqsim-stubs/api/__init__.pyi

@@ -1,5 +1,5 @@
-
 import sys
+
 if sys.version_info >= (3, 8):
     from typing import Protocol
 else:
@@ -8,7 +8,6 @@ else:
 import jneqsim.api.ioc
 import typing
 
-
 class __module_protocol__(Protocol):
     # A module protocol which reflects the result of ``jp.JPackage("jneqsim.api")``.
 

src/jneqsim-stubs/api/ioc/__init__.pyi

@@ -1,5 +1,5 @@
-
 import sys
+
 if sys.version_info >= (3, 8):
     from typing import Protocol
 else:
@@ -9,16 +9,19 @@ import java.lang
 import jpype
 import typing
 
-
-
 class CalculationResult:
     fluidProperties: typing.MutableSequence[typing.MutableSequence[float]] = ...
     calculationError: typing.MutableSequence[java.lang.String] = ...
-    def __init__(self, doubleArray: typing.Union[typing.List[typing.MutableSequence[float]], jpype.JArray], stringArray: typing.Union[typing.List[java.lang.String], jpype.JArray]): ...
+    def __init__(
+        self,
+        doubleArray: typing.Union[
+            typing.List[typing.MutableSequence[float]], jpype.JArray
+        ],
+        stringArray: typing.Union[typing.List[java.lang.String], jpype.JArray],
+    ): ...
     def equals(self, object: typing.Any) -> bool: ...
     def hashCode(self) -> int: ...
 
-
 class __module_protocol__(Protocol):
     # A module protocol which reflects the result of ``jp.JPackage("jneqsim.api.ioc")``.
 

src/jneqsim-stubs/blackoil/__init__.pyi

@@ -1,5 +1,5 @@
-
 import sys
+
 if sys.version_info >= (3, 8):
     from typing import Protocol
 else:
@@ -12,24 +12,42 @@ import jneqsim.blackoil.io
 import jneqsim.thermo.system
 import typing
 
-
-
 class BlackOilConverter:
     def __init__(self): ...
     @staticmethod
-    def convert(systemInterface: jneqsim.thermo.system.SystemInterface, double: float, doubleArray: typing.Union[typing.List[float], jpype.JArray], double3: float, double4: float) -> 'BlackOilConverter.Result': ...
+    def convert(
+        systemInterface: jneqsim.thermo.system.SystemInterface,
+        double: float,
+        doubleArray: typing.Union[typing.List[float], jpype.JArray],
+        double3: float,
+        double4: float,
+    ) -> "BlackOilConverter.Result": ...
+
     class Result:
-        pvt: 'BlackOilPVTTable' = ...
-        blackOilSystem: 'SystemBlackOil' = ...
+        pvt: "BlackOilPVTTable" = ...
+        blackOilSystem: "SystemBlackOil" = ...
         rho_o_sc: float = ...
         rho_g_sc: float = ...
         rho_w_sc: float = ...
         bubblePoint: float = ...
         def __init__(self): ...
 
 class BlackOilFlash(java.io.Serializable):
-    def __init__(self, blackOilPVTTable: 'BlackOilPVTTable', double: float, double2: float, double3: float): ...
-    def flash(self, double: float, double2: float, double3: float, double4: float, double5: float) -> 'BlackOilFlashResult': ...
+    def __init__(
+        self,
+        blackOilPVTTable: "BlackOilPVTTable",
+        double: float,
+        double2: float,
+        double3: float,
+    ): ...
+    def flash(
+        self,
+        double: float,
+        double2: float,
+        double3: float,
+        double4: float,
+        double5: float,
+    ) -> "BlackOilFlashResult": ...
 
 class BlackOilFlashResult(java.io.Serializable):
     O_std: float = ...
@@ -52,7 +70,9 @@ class BlackOilFlashResult(java.io.Serializable):
     def __init__(self): ...
 
 class BlackOilPVTTable(java.io.Serializable):
-    def __init__(self, list: java.util.List['BlackOilPVTTable.Record'], double: float): ...
+    def __init__(
+        self, list: java.util.List["BlackOilPVTTable.Record"], double: float
+    ): ...
     def Bg(self, double: float) -> float: ...
     def Bo(self, double: float) -> float: ...
     def Bw(self, double: float) -> float: ...
@@ -63,6 +83,7 @@ class BlackOilPVTTable(java.io.Serializable):
     def mu_g(self, double: float) -> float: ...
     def mu_o(self, double: float) -> float: ...
     def mu_w(self, double: float) -> float: ...
+
     class Record(java.io.Serializable):
         p: float = ...
         Rs: float = ...
@@ -73,11 +94,28 @@ class BlackOilPVTTable(java.io.Serializable):
         Rv: float = ...
         Bw: float = ...
         mu_w: float = ...
-        def __init__(self, double: float, double2: float, double3: float, double4: float, double5: float, double6: float, double7: float, double8: float, double9: float): ...
+        def __init__(
+            self,
+            double: float,
+            double2: float,
+            double3: float,
+            double4: float,
+            double5: float,
+            double6: float,
+            double7: float,
+            double8: float,
+            double9: float,
+        ): ...
 
 class SystemBlackOil(java.io.Serializable):
-    def __init__(self, blackOilPVTTable: BlackOilPVTTable, double: float, double2: float, double3: float): ...
-    def copyShallow(self) -> 'SystemBlackOil': ...
+    def __init__(
+        self,
+        blackOilPVTTable: BlackOilPVTTable,
+        double: float,
+        double2: float,
+        double3: float,
+    ): ...
+    def copyShallow(self) -> "SystemBlackOil": ...
     def flash(self) -> BlackOilFlashResult: ...
     def getBg(self) -> float: ...
     def getBo(self) -> float: ...
@@ -102,7 +140,6 @@ class SystemBlackOil(java.io.Serializable):
     def setStdTotals(self, double: float, double2: float, double3: float) -> None: ...
     def setTemperature(self, double: float) -> None: ...
 
-
 class __module_protocol__(Protocol):
     # A module protocol which reflects the result of ``jp.JPackage("jneqsim.blackoil")``.