In order to support the evolving GeoPoint encodings in Lucene 5 and 6, ES 2.x and 5.x implements an abstraction layer to the GeoPointFieldMapper classes. As of 5.x the geo_point field mapper settled on using Lucene's more performant LatLonPoint field type and deprecated all other encodings. In 6.0 all encodings except LatLonPoint have been removed rendering this abstraction layer useless. This commit removes the abstraction layer and renames the LatLonPointFieldMapper back to GeoPointFieldMapper to mantain consistency with ES field naming.
This change adds a strict mode for xcontent parsing on the rest layer. The strict mode will be off by default for 5.x and in a separate commit will be enabled by default for 6.0. The strict mode, which can be enabled by setting `http.content_type.required: true` in 5.x, will require that all incoming rest requests have a valid and supported content type header before the request is dispatched. In the non-strict mode, the Content-Type header will be inspected and if it is not present or not valid, we will continue with auto detection of content like we have done previously.
The content type header is parsed to the matching XContentType value with the only exception being for plain text requests. This value is then passed on with the content bytes so that we can reduce the number of places where we need to auto-detect the content type.
As part of this, many transport requests and builders were updated to provide methods that
accepted the XContentType along with the bytes and the methods that would rely on auto-detection have been deprecated.
In the non-strict mode, deprecation warnings are issued whenever a request with body doesn't provide the Content-Type header.
See #19388
Currently, stored scripts use a namespace of (lang, id) to be put, get, deleted, and executed. This is not necessary since the lang is stored with the stored script. A user should only have to specify an id to use a stored script. This change makes that possible while keeping backwards compatibility with the previous namespace of (lang, id). Anywhere the previous namespace is used will log deprecation warnings.
The new behavior is the following:
When a user specifies a stored script, that script will be stored under both the new namespace and old namespace.
Take for example script 'A' with lang 'L0' and data 'D0'. If we add script 'A' to the empty set, the scripts map will be ["A" -- D0, "A#L0" -- D0]. If a script 'A' with lang 'L1' and data 'D1' is then added, the scripts map will be ["A" -- D1, "A#L1" -- D1, "A#L0" -- D0].
When a user deletes a stored script, that script will be deleted from both the new namespace (if it exists) and the old namespace.
Take for example a scripts map with {"A" -- D1, "A#L1" -- D1, "A#L0" -- D0}. If a script is removed specified by an id 'A' and lang null then the scripts map will be {"A#L0" -- D0}. To remove the final script, the deprecated namespace must be used, so an id 'A' and lang 'L0' would need to be specified.
When a user gets/executes a stored script, if the new namespace is used then the script will be retrieved/executed using only 'id', and if the old namespace is used then the script will be retrieved/executed using 'id' and 'lang'
This commit adds a SpecialPermission constant and uses that constant
opposed to introducing new instances everywhere.
Additionally, this commit introduces a single static method to check that
the current code has permission. This avoids all the duplicated access
blocks that exist currently.
* Upgrade to Lucene 6.4.0
`ValueSource`s are now converted to `DoubleValueSource`s using the Lucene adapter made for the migration to the new API in 6.4.0.
* Remove a checked exception, replacing it with `ParsingException`.
* Remove all Parser classes for the yaml sections, replacing them with static methods.
* Remove `ClientYamlTestFragmentParser`. Isn't used any more.
* Remove `ClientYamlTestSuiteParseContext`, replacing it with some static utility methods.
I did not rewrite the parsers using `ObjectParser` because I don't think it is worth it right now.
With this commit we enable the Jackson feature 'STRICT_DUPLICATE_DETECTION'
by default. This ensures that JSON keys are always unique. While this has
a performance impact, benchmarking has indicated that the typical drop in
indexing throughput is around 1 - 2%.
As a last resort, we allow users to still disable strict duplicate checks
by setting `-Des.json.strict_duplicate_detection=false` which is
intentionally undocumented.
Closes#19614
For the record, I also had to remove the geo-hash cell and geo-distance range
queries to make the code compile. These queries already throw an exception in
all cases with 5.x indices, so that does not hurt any more.
I also had to rename all 2.x bwc indices from `index-${version}` to
`unsupported-${version}` to make `OldIndexBackwardCompatibilityIT`
happy.
Set lucene version to 6.4.0-snapshot-ec38570 and update all the sha1s/license
Fix invalid combo after upgrade in query_string query. split_on_whitespace=false is disallowed if auto_generate_phrase_queries=true
Adapt the expectations of some tests to the new format of the Lucene explain output
At one point in the past when moving out the rest tests from core to
their own subproject, we had multiple test classes which evenly split up
the tests to run. However, we simplified this and went back to a single
test runner to have better reproduceability in tests. This change
removes the remnants of that multiplexing support.
Lucene 6.3 is expected to be released in the next weeks so it'd be good to give
it some integration testing. I had to upgrade randomized-testing too so that
both Lucene and Elasticsearch are on the same version.
I also reduced the visibility of a couple classes and renamed/consolidated some
test classes for consistency, eg. removing the `Simple` prefix or using the
`<Type>FieldMapperTests` convention for testing field mappers.
When compiling many dynamically changing scripts, parameterized
scripts (<https://www.elastic.co/guide/en/elasticsearch/reference/master/modules-scripting-using.html#prefer-params>)
should be preferred. This enforces a limit to the number of scripts that
can be compiled within a minute. A new dynamic setting is added -
`script.max_compilations_per_minute`, which defaults to 15.
If more dynamic scripts are sent, a user will get the following
exception:
```json
{
"error" : {
"root_cause" : [
{
"type" : "circuit_breaking_exception",
"reason" : "[script] Too many dynamic script compilations within one minute, max: [15/min]; please use on-disk, indexed, or scripts with parameters instead",
"bytes_wanted" : 0,
"bytes_limit" : 0
}
],
"type" : "search_phase_execution_exception",
"reason" : "all shards failed",
"phase" : "query",
"grouped" : true,
"failed_shards" : [
{
"shard" : 0,
"index" : "i",
"node" : "a5V1eXcZRYiIk8lecjZ4Jw",
"reason" : {
"type" : "general_script_exception",
"reason" : "Failed to compile inline script [\"aaaaaaaaaaaaaaaa\"] using lang [painless]",
"caused_by" : {
"type" : "circuit_breaking_exception",
"reason" : "[script] Too many dynamic script compilations within one minute, max: [15/min]; please use on-disk, indexed, or scripts with parameters instead",
"bytes_wanted" : 0,
"bytes_limit" : 0
}
}
}
],
"caused_by" : {
"type" : "general_script_exception",
"reason" : "Failed to compile inline script [\"aaaaaaaaaaaaaaaa\"] using lang [painless]",
"caused_by" : {
"type" : "circuit_breaking_exception",
"reason" : "[script] Too many dynamic script compilations within one minute, max: [15/min]; please use on-disk, indexed, or scripts with parameters instead",
"bytes_wanted" : 0,
"bytes_limit" : 0
}
}
},
"status" : 500
}
```
This also fixes a bug in `ScriptService` where requests being executed
concurrently on a single node could cause a script to be compiled
multiple times (many in the case of a powerful node with many shards)
due to no synchronization between checking the cache and compiling the
script. There is now synchronization so that a script being compiled
will only be compiled once regardless of the number of concurrent
searches on a node.
Relates to #19396
Currently both aggregations really share the same implementation. This commit
splits the implementations so that regular histograms can support decimal
intervals/offsets and compute correct buckets for negative decimal values.
However the response API is still the same. So for intance both regular
histograms and date histograms will produce an
`org.elasticsearch.search.aggregations.bucket.histogram.Histogram`
aggregation.
The optimization to compute an identifier of the rounded value and the
rounded value itself has been removed since it was only used by regular
histograms, which now do the rounding themselves instead of relying on the
Rounding abstraction.
Closes#8082Closes#4847
This makes it obvious that these tests are for running the client yaml
suites. Now that there are other ways of running tests using the REST
client against a running cluster we can't go on calling the shared
client yaml tests "REST tests". They are rest tests, but they aren't
**the** rest tests.
This adds a header that looks like `Location: /test/test/1` to the
response for the index/create/update API. The requirement for the header
comes from https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.htmlhttps://tools.ietf.org/html/rfc7231#section-7.1.2 claims that relative
URIs are OK. So we use an absolute path which should resolve to the
appropriate location.
Closes#19079
This makes large changes to our rest test infrastructure, allowing us
to write junit tests that test a running cluster via the rest client.
It does this by splitting ESRestTestCase into two classes:
* ESRestTestCase is the superclass of all tests that use the rest client
to interact with a running cluster.
* ESClientYamlSuiteTestCase is the superclass of all tests that use the
rest client to run the yaml tests. These tests are shared across all
official clients, thus the `ClientYamlSuite` part of the name.
Registering a script engine or native scripts still uses Guice today
and is much more complicated than needed. This change moves to a pull
based model where script plugins have to implement a dedicated interface
`ScriptPlugin` and defines simple getter returning instances rather than
classes.
In 2.0 we added plugin descriptors which require defining a name and
description for the plugin. However, we still have name() and
description() which must be overriden from the Plugin class. This still
exists for classpath plugins. But classpath plugins are mainly for
tests, and even then, referring to classpath plugins with their class is
a better idea. This change removes name() and description(), replacing
the name for classpath plugins with the full class name.
This change makes ES compile with java9 again, build 118.
* There are a handful of changes due to failure to determine types during compile.
* The attachment plugins which use tika needed to have tika upgraded in order to pickup fixes there for java 9.
* azure discovery and s3 repository indirectly depend on jaxb, which is no longer in the default modules. They now add a jaxb dependency externally, and make JarHell allow for this package.
This removes the ScriptMode class entirely, which was an enum with two
options (ON and OFF) which essentially boiled down to true and false.
Now the boolean values are used instead.
Previously multiple extensions could be provided, however, this can lead
to confusion with on-disk scripts (ie, "foo.js" and "foo.javascript")
having different content. Only a single extension is now supported.
The only language currently supporting multiple extensions was the
Javascript engine ("js" and "javascript"). It now only supports the
`.js` extension.
Relates to #10598
This removes all the mentions of the sandbox from the script engine
services and permissions model. This means that the following settings
are no longer supported:
```yaml
script.inline: sandbox
script.stored: sandbox
```
Instead, only a `true` or `false` value can be specified.
Since this would otherwise break the default-allow parameter for
languages like expressions, painless, and mustache, all script engines
have been updated to have individual settings, for instance:
```yaml
script.engine.groovy.inline: true
```
Would enable all inline scripts for groovy. (they can still be
overridden on a per-operation basis).
Expressions, Painless, and Mustache all default to `true` for inline,
file, and stored scripts to preserve the old scripting behavior.
Resolves#17114
This makes all numeric fields including `date`, `ip` and `token_count` use
points instead of the inverted index as a lookup structure. This is expected
to perform worse for exact queries, but faster for range queries. It also
requires less storage.
Notes about how the change works:
- Numeric mappers have been split into a legacy version that is essentially
the current mapper, and a new version that uses points, eg.
LegacyDateFieldMapper and DateFieldMapper.
- Since new and old fields have the same names, the decision about which one
to use is made based on the index creation version.
- If you try to force using a legacy field on a new index or a field that uses
points on an old index, you will get an exception.
- IP addresses now support IPv6 via Lucene's InetAddressPoint and store them
in SORTED_SET doc values using the same encoding (fixed length of 16 bytes
and sortable).
- The internal MappedFieldType that is stored by the new mappers does not have
any of the points-related properties set. Instead, it keeps setting the index
options when parsing the `index` property of mappings and does
`if (fieldType.indexOptions() != IndexOptions.NONE) { // add point field }`
when parsing documents.
Known issues that won't fix:
- You can't use numeric fields in significant terms aggregations anymore since
this requires document frequencies, which points do not record.
- Term queries on numeric fields will now return constant scores instead of
giving better scores to the rare values.
Known issues that we could work around (in follow-up PRs, this one is too large
already):
- Range queries on `ip` addresses only work if both the lower and upper bounds
are inclusive (exclusive bounds are not exposed in Lucene). We could either
decide to implement it, or drop range support entirely and tell users to
query subnets using the CIDR notation instead.
- Since IP addresses now use a different representation for doc values,
aggregations will fail when running a terms aggregation on an ip field on a
list of indices that contains both pre-5.0 and 5.0 indices.
- The ip range aggregation does not work on the new ip field. We need to either
implement range aggs for SORTED_SET doc values or drop support for ip ranges
and tell users to use filters instead. #17700Closes#16751Closes#17007Closes#11513
In both cases, what elasticsearch is really interested in is whether the field
is an analyzed string field. So it can just check `tokenized()` instead.
* upgrades numerics to new Point format
* updates geo api changes
* adds GeoPointDistanceRangeQuery as XGeoPointDistanceRangeQuery
* cuts over to ES GeoHashUtils
`text` fields will have fielddata disabled by default. Fielddata can still be
enabled on an existing index by setting `fielddata=true` in the mappings.
Closes#16964
Squashed commit of the following:
commit a23f9d2d29220991aa498214530753d7a5a148c6
Merge: eec9c4e 0b0a251
Author: Robert Muir <rmuir@apache.org>
Date: Mon Mar 7 04:12:02 2016 -0500
Merge branch 'master' into lucene6
commit eec9c4e5cd11e9c3e0b426f04894bb2a6dae4f21
Merge: bc67205 675d940
Author: Robert Muir <rmuir@apache.org>
Date: Fri Mar 4 13:45:00 2016 -0500
Merge branch 'master' into lucene6
commit bc67205bdfe1526eae277ab7856fc050ecbdb7b2
Author: Robert Muir <rmuir@apache.org>
Date: Fri Mar 4 09:56:31 2016 -0500
fix test bug
commit a60723b007ff12d97b1810cef473bd7b553a0327
Author: Simon Willnauer <simonw@apache.org>
Date: Fri Mar 4 15:35:35 2016 +0100
Fix SimpleValidateQueryIT to put braces around boosted terms
commit ae3a49d7ba7ced448d2a5262e5d8ec98671a9090
Author: Simon Willnauer <simonw@apache.org>
Date: Fri Mar 4 15:27:25 2016 +0100
fix multimatchquery
commit ae23fdb88a8f6d3fb7ba60fd1aaf3fd72d899aa5
Author: Simon Willnauer <simonw@apache.org>
Date: Fri Mar 4 15:20:49 2016 +0100
Rewrite DecayFunctionScoreIT to be independent of the similarity used
This test relied a lot on the term scoring and compared scores
that are dependent on the similarity. This commit changes the base query
to be a predictable constant score query.
commit 366c2d518c35d31251033f1b6f6a93f6e2ae327d
Author: Simon Willnauer <simonw@apache.org>
Date: Fri Mar 4 14:06:14 2016 +0100
Fix scoring in tests due to changes to idf calculation.
Lucene 6 uses a different default similarity as well as a different
way to calculate IDF. In contrast to older version lucene 6 uses docCount per field
to calculate the IDF not the # of docs in the index to overcome the sparse field
cases.
commit dac99fd64ac2fa71b8d8d106fe68825e574c49f8
Author: Robert Muir <rmuir@apache.org>
Date: Fri Mar 4 08:21:57 2016 -0500
don't hardcoded expected termquery score
commit 6e9f340ba49ab10eed512df86d52a121aa775b0f
Author: Robert Muir <rmuir@apache.org>
Date: Fri Mar 4 08:04:45 2016 -0500
suppress deprecation warning until migrated to points
commit 3ac8908424b3fdad44a90a4f7bdb3eff7efd077d
Author: Robert Muir <rmuir@apache.org>
Date: Fri Mar 4 07:21:43 2016 -0500
Remove invalid test: all commits have IDs, and its illegal to do this.
commit c12976288124ad1a26467e7e848fb810548e7eab
Author: Robert Muir <rmuir@apache.org>
Date: Fri Mar 4 07:06:14 2016 -0500
don't test with unsupported back compat
commit 18bbfe76128570bc70883bf91ff4c44c82d27817
Author: Robert Muir <rmuir@apache.org>
Date: Fri Mar 4 07:02:18 2016 -0500
remove now invalid lucene 4 backcompat test
commit 7e730e572886f0ef2d3faba712e4256216ff01ec
Author: Robert Muir <rmuir@apache.org>
Date: Fri Mar 4 06:58:52 2016 -0500
remove now invalid lucene 4 backwards test
commit 244d2ab6868ba5ac9e0bcde3c2833743751a25ec
Author: Robert Muir <rmuir@apache.org>
Date: Fri Mar 4 06:47:23 2016 -0500
use 6.0 codec
commit 5f64d4a431a6fdaa1234adca23f154c2a1de8284
Author: Robert Muir <rmuir@apache.org>
Date: Fri Mar 4 06:43:08 2016 -0500
compile, javadocs, forbidden-apis, etc
commit 1f273cd62a7fe9ca8f8944acbbfc5cbdd3d81ccb
Merge: cd33921 29e3443
Author: Simon Willnauer <simonw@apache.org>
Date: Fri Mar 4 10:45:29 2016 +0100
Merge branch 'master' into lucene6
commit cd33921ac742ef9fb351012eff35f3c7dbda7264
Author: Robert Muir <rmuir@apache.org>
Date: Thu Mar 3 23:58:37 2016 -0500
fix hunspell dictionary loading
commit c7fdbd837b01f7defe9cb1c24e2ec65604b0dc96
Merge: 4d4190f d8948ba
Author: Robert Muir <rmuir@apache.org>
Date: Thu Mar 3 23:41:53 2016 -0500
Merge branch 'master' into lucene6
commit 4d4190fd82601aaafac6b8254ccb3edf218faa34
Author: Robert Muir <rmuir@apache.org>
Date: Thu Mar 3 23:39:14 2016 -0500
remove nocommit
commit 77ca69e288b1a41aa9595c921ed166c272a00ea8
Author: Robert Muir <rmuir@apache.org>
Date: Thu Mar 3 23:38:24 2016 -0500
clean up numericutils vs legacynumericutils
commit a466d696fbaad04b647ffbc0857a9439b583d0bf
Author: Robert Muir <rmuir@apache.org>
Date: Thu Mar 3 23:32:43 2016 -0500
upgrade spatial4j
commit 5412c747a8cfe638bacedbc8233163cb75cc3dc5
Author: Robert Muir <rmuir@apache.org>
Date: Thu Mar 3 23:19:28 2016 -0500
move to 6.0.0-snapshot-8eada27
commit b32bfe924626b87e540692375ece09e7c2edb189
Author: Adrien Grand <jpountz@gmail.com>
Date: Thu Mar 3 11:30:09 2016 +0100
Fix some test compile errors.
commit 6ccde35e9840b03c68d1a2cd47c7923a06edf64a
Author: Adrien Grand <jpountz@gmail.com>
Date: Thu Mar 3 11:25:51 2016 +0100
Current Lucene version is 6.0.0.
commit f62e1015d931b4cc04c778298a8fa1ba65e97ad9
Author: Adrien Grand <jpountz@gmail.com>
Date: Thu Mar 3 11:20:48 2016 +0100
Fix compile errors in NGramTokenFilterFactory.
commit 6837c6eabf96075f743649da9b9b52dd39611c58
Author: Adrien Grand <jpountz@gmail.com>
Date: Thu Mar 3 10:50:59 2016 +0100
Fix the edge ngram tokenizer/filter.
commit ccd7f070de5efcdfbeb34b9555c65c4990bf1ba6
Author: Adrien Grand <jpountz@gmail.com>
Date: Thu Mar 3 10:42:44 2016 +0100
The missing value is now accessible through a getter.
commit bd3b77f9b28e5b05daa3d49683a9922a6baf2963
Author: Adrien Grand <jpountz@gmail.com>
Date: Thu Mar 3 10:41:51 2016 +0100
Remove IndexCacheableQuery.
commit 05f3091c347aeae80eeb16349ac51d2b53cf86f7
Author: Adrien Grand <jpountz@gmail.com>
Date: Thu Mar 3 10:39:43 2016 +0100
Fix compilation of function_score queries.
commit 81cda79a2431ac78f56b0cc5a5765387f662d801
Author: Adrien Grand <jpountz@gmail.com>
Date: Thu Mar 3 10:35:02 2016 +0100
Fix compile errors in BlendedTermQuery.
commit 70994ce8dd1eca0b995870974a38e20f26f96a7b
Author: Robert Muir <rmuir@apache.org>
Date: Wed Mar 2 23:33:03 2016 -0500
add bug ID
commit 29d4f1a71f36f646b5a6060bed3db019564a279d
Author: Robert Muir <rmuir@apache.org>
Date: Wed Mar 2 21:02:32 2016 -0500
easy .store changes
commit 5e1a1e6fd665fa455e88d3a8987362fad5f44bb1
Author: Robert Muir <rmuir@apache.org>
Date: Wed Mar 2 20:47:24 2016 -0500
cleanups mostly around boosting
commit 333a669ec6c305ada5645d13ed1da0e19ec1d053
Author: Robert Muir <rmuir@apache.org>
Date: Wed Mar 2 20:27:56 2016 -0500
more simple fixes
commit bd5cd98a1e089c866b6b4a5e159400b110140ce6
Author: Robert Muir <rmuir@apache.org>
Date: Wed Mar 2 19:49:38 2016 -0500
more easy fixes and removal of ancient cruft
commit a68f419ee47da5f9c9ce5b372f01d707e902474c
Author: Robert Muir <rmuir@apache.org>
Date: Wed Mar 2 19:35:02 2016 -0500
cutover numerics
commit 4ca5dc1fa47dd5892db00899032133318fff3116
Author: Robert Muir <rmuir@apache.org>
Date: Wed Mar 2 18:34:18 2016 -0500
fix some constants
commit 88710a17817086e477c6c021ec346d0534b7fb88
Author: Robert Muir <rmuir@apache.org>
Date: Wed Mar 2 18:14:25 2016 -0500
Add spatial-extras jar as a core dependency
commit c8cd6726583e5ce3f546ed355d4eca037164a30d
Author: Robert Muir <rmuir@apache.org>
Date: Wed Mar 2 18:03:33 2016 -0500
update to lucene 6 jars
This commit enableds strict settings validation on node startup. All settings
passed to elasticsearch either through system properties, yaml files or any other
way to pass settings must be registered and valid. Settings that are unknown ie. due to
typos or due to deprecation or removal will cause the node to NOT start up. Plugins
have to declare all their settings on the `SettingsModule#registerSetting` and settings for
plugins that are not installed must be removed.
This commit also removes the ability to specify the nodes name via `-Des.name` or just `name` in the
configuration files. The node name must be prefixed with the node prexif like `node.name: Boom`. Left over
usage of `name` will also cause startup to fail.
This commit method renames the ScriptEngineService interface methods
types, extensions, and sandboxed to getTypes, getExtensions, and
isSandboxed, respectively.
This commit converts the script mode settings to the new settings
infrastructure. This is a major refactoring of the handling of script
mode settings. This refactoring is necessary because these settings are
determined at runtime based on the registered script engines and the
registered script contexts.
The rest test framework, because it used to be tightly integrated with
ESIntegTestCase, currently expects the addresses for the test cluster to
be passed using the transport protocol port. However, it only uses this
to then find the http address.
This change makes ESRestTestCase extend from ESTestCase instead of
ESIntegTestCase, and changes the sysprop used to tests.rest.cluster,
which now takes the http address.
closes#15459
Site plugins used to be used for things like kibana and marvel, but
there is no longer a need since kibana (and marvel as a kibana plugin)
uses node.js. This change removes site plugins, as well as the flag for
jvm plugins. Now all plugins are jvm plugins.
This fixes the `lenient` parameter to be `missingClasses`. I will remove this boolean and we can handle them via the normal whitelist.
It also adds a check for sheisty classes (jar hell with the jdk).
This is inspired by the lucene "sheisty" classes check, but it has false positives. This check is more evil, it validates every class file against the extension classloader as a resource, to see if it exists there. If so: jar hell.
This jar hell is a problem for several reasons:
1. causes insanely-hard-to-debug problems (like bugs in forbidden-apis)
2. hides problems (like internal api access)
3. the code you think is executing, is not really executing
4. security permissions are not what you think they are
5. brings in unnecessary dependencies
6. its jar hell
The more difficult problems are stuff like jython, where these classes are simply 'uberjared' directly in, so you cant just fix them by removing a bogus dependency. And there is a legit reason for them to do that, they want to support java 1.4.
Since 2.2 we run all scripts with minimal privileges, similar to applets in your browser.
The problem is, they have unrestricted access to other things they can muck with (ES, JDK, whatever).
So they can still easily do tons of bad things
This PR restricts what classes scripts can load via the classloader mechanism, to make life more difficult.
The "standard" list was populated from the old list used for the groovy sandbox: though
a few more were needed for tests to pass (java.lang.String, java.util.Iterator, nothing scary there).
Additionally, each scripting engine typically needs permissions to some runtime stuff.
That is the downside of this "good old classloader" approach, but I like the transparency and simplicity,
and I don't want to waste my time with any feature provided by the engine itself for this, I don't trust them.
This is not perfect and the engines are not perfect but you gotta start somewhere. For expert users that
need to tweak the permissions, we already support that via the standard java security configuration files, the
specification is simple, supports wildcards, etc (though we do not use them ourselves).