allenai · joelgrus · Oct 2, 2018 · Oct 2, 2018 · Oct 2, 2018 · Oct 2, 2018
diff --git a/allennlp/common/checks.py b/allennlp/common/checks.py
@@ -4,7 +4,7 @@
 """
 
 import logging
-
+import subprocess
 from torch import cuda
 
 logger = logging.getLogger(__name__)  # pylint: disable=invalid-name
@@ -43,3 +43,10 @@ def check_for_gpu(device_id: int):
         raise ConfigurationError("Experiment specified a GPU but none is available;"
                                  " if you want to run on CPU use the override"
                                  " 'trainer.cuda_device=-1' in the json config file.")
+
+def check_for_java() -> bool:
+    try:
+        java_version = subprocess.check_output(['java', '-version'], stderr=subprocess.STDOUT)
+        return 'version' in java_version.decode()
+    except FileNotFoundError:
+        return False
diff --git a/allennlp/predictors/wikitables_parser.py b/allennlp/predictors/wikitables_parser.py
@@ -11,6 +11,7 @@
 from allennlp.data import DatasetReader, Instance
 from allennlp.models import Model
 from allennlp.predictors.predictor import Predictor
+from allennlp.common.checks import check_for_java
 
 # TODO(mattg): We should merge how this works with how the `WikiTablesAccuracy` metric works, maybe
 # just removing the need for adding this stuff at all, because the parser already runs the java
@@ -106,6 +107,8 @@ def _execute_logical_form_on_table(logical_form: str, table: str):
         # TODO(matt): The jar that we have isn't optimal for this use case - we're using a
         # script designed for computing accuracy, and just pulling out a piece of it. Writing
         # a new entry point to the jar that's tailored for this use would be cleaner.
+        if not check_for_java():
+            raise RuntimeError('Java is not installed properly.')
         command = ' '.join(['java',
                             '-jar',
                             cached_path(DEFAULT_EXECUTOR_JAR),

diff --git a/allennlp/semparse/executors/wikitables_sempre_executor.py b/allennlp/semparse/executors/wikitables_sempre_executor.py
@@ -6,6 +6,7 @@
 import subprocess
 
 from allennlp.common.file_utils import cached_path
+from allennlp.common.checks import check_for_java
 
 logger = logging.getLogger(__name__)  # pylint: disable=invalid-name
 
@@ -81,6 +82,8 @@ def _create_sempre_executor(self) -> None:
             subprocess.run(f'wget {GROW_FILE}', shell=True)
             subprocess.run(f'mv wikitables-grow.grammar {grammar_path}', shell=True)
 
+        if not check_for_java():
+            raise RuntimeError('Java is not installed properly.')
         args = ['java', '-jar', cached_path(SEMPRE_EXECUTOR_JAR), 'serve', self._table_directory]
         self._executor_process = subprocess.Popen(args,
                                                   stdin=subprocess.PIPE,