Netbeans 8.1 crashes when opening files like json, php, etc
Netbeans 8.0.2 behaves as above.
Downloaded Netbeans 8.1 from the official site, installed on a new system user keeps with the same behaviour.
For me, it happens with anyone of the following VMs.

$ eselect java-vm list
Available Java Virtual Machines:
[1] oracle-jdk-bin-1.7
[2] oracle-jdk-bin-1.8 system-vm user-vm
[3] oracle-jre-bin-1.7
[4] oracle-jre-bin-1.8

$ equery u netbeans
!!! Section 'funtoo-kde-overlay' in repos.conf has name different from repository name 'kde' set inside repository
!!! Section 'funtoo-kde-overlay' in repos.conf has name different from repository name 'kde' set inside repository
!!! Section 'funtoo-kde-overlay' in repos.conf has name different from repository name 'kde' set inside repository
[ Legend : U - final flag setting for installation]
[ : I - package is installed with flag ]
[ Colors : set, unset ]

• Found these USE flags for dev-util/netbeans-8.1:
  U I

• - doc : Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
• - linguas_af : Afrikaans locale
• - linguas_ar : Arabic locale
• - linguas_ar_SA : Arabic locale for Saudi-Arabia
• - linguas_bg : Bulgarian locale
• - linguas_ca : Catalan locale
• - linguas_cs : Czech locale
• - linguas_de : German locale
• - linguas_el : Greek locale
  + + linguas_es : Spanish locale
• - linguas_es_CO : Spanish locale for Columbia
• - linguas_fil : Filipino locale
• - linguas_fr : French locale
• - linguas_gl : Galician locale
• - linguas_hi_IN : Hindi locale
• - linguas_id_ID : Indonesian locale
• - linguas_it : Italian locale
• - linguas_ja : Japanese locale
• - linguas_ko : Korean locale
• - linguas_lt : Lithuanian locale
• - linguas_nl_BE : Dutch locale for Belgium (Flemish)
• - linguas_nl_NL : Dutch locale for the Netherlands
• - linguas_pl : Polish locale
• - linguas_pt_BR : Portuguese locale for Brasil
• - linguas_pt_PT : Portuguese locale for Portugal
• - linguas_ro : Romanian locale
• - linguas_ru : Russian locale
• - linguas_si : Sinhala locale
• - linguas_sq : Albanian locale
• - linguas_sr : Serbian locale
• - linguas_sv : Swedish locale
• - linguas_ta_IN : Tamil locale
• - linguas_tr : Turkish locale
• - linguas_vi : Vietnamese locale
• - linguas_zh_CN : Chinese locale for Peoples Republic of China
• - linguas_zh_TW : Chinese locale for Taiwan
  + + netbeans_modules_apisupport : enables apisupport module
• - netbeans_modules_cnd : enables C/C++ development support
• - netbeans_modules_dlight : enables framework for creation of Observability Tools using DTrace
• - netbeans_modules_enterprise : enables enterprise development support
• - netbeans_modules_ergonomics : enables ergonomics features
• - netbeans_modules_extide : enables extide module
• - netbeans_modules_groovy : enables Groovy and Grails development support
• - netbeans_modules_java : enables Java development support
• - netbeans_modules_javacard : enables cluster for JavaCard development
• - netbeans_modules_javafx : enables JavaFX development support
• - netbeans_modules_mobility : enables support for development of mobile applications
  + + netbeans_modules_php : enables PHP development support
• - netbeans_modules_profiler : enables Java profiler
• - netbeans_modules_webcommon : enables javascript libraries and web client tools
  + + netbeans_modules_websvccommon : enables common support for web services development

Here is the output when launching netbeans through bash and then opening a json file within netbeans:

$ netbeans-8.1
#

1. A fatal error has been detected by the Java Runtime Environment:
   #
2. SIGSEGV (0xb) at pc=0x00007fdf671f0a1e, pid=7019, tid=140597499262720
   #
3. JRE version: Java(TM) SE Runtime Environment (8.0_66-b17) (build 1.8.0_66-b17)
4. Java VM: Java HotSpot(TM) 64-Bit Server VM (25.66-b17 mixed mode linux-amd64 compressed oops)
5. Problematic frame:
6. C [jna4029674182784232406.tmp+0x8a1e] Java_com_sun_jna_Native_getInt+0x1e
   #
7. Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
   #
8. An error report file with more information is saved as:
9. /home/sibok/public_html/IES_JOANDAUSTRIA/M7/UF2/DAW_M7_UF3_AC1/sf2/hs_err_pid7019.log
   #
10. If you would like to submit a bug report, please visit:
11. http://bugreport.java.com/bugreport/crash.jsp
12. The crash happened outside the Java Virtual Machine in native code.
13. See problematic frame for where to report the bug.
    #
    /usr/share/netbeans-nb-8.1/platform/lib/nbexec: line 474: 7019 Aborted "/opt/oracle-jdk-bin-1.8.0.66/bin/java" Djdk.home="/opt/oracle-jdk-bin-1.8.0.66" -classpath "/usr/share/netbeans-nb-8.1/platform/lib/boot.jar:/usr/share/netbeans-nb-8.1/platform/lib/org-openide-modules.jar:/usr/share/netbeans-nb-8.1/platform/lib/org-openide-util-lookup.jar:/usr/share/netbeans-nb-8.1/platform/lib/org-openide-util-ui.jar:/usr/share/netbeans-nb-8.1/platform/lib/org-openide-util.jar:/usr/share/netbeans-nb-8.1/platform/lib/locale/boot_es.jar:/usr/share/netbeans-nb-8.1/platform/lib/locale/boot_es_CO.jar:/usr/share/netbeans-nb-8.1/platform/lib/locale/org-openide-modules_es.jar:/usr/share/netbeans-nb-8.1/platform/lib/locale/org-openide-modules_es_CO.jar:/usr/share/netbeans-nb-8.1/platform/lib/locale/org-openide-util-lookup_es.jar:/usr/share/netbeans-nb-8.1/platform/lib/locale/org-openide-util-lookup_es_CO.jar:/usr/share/netbeans-nb-8.1/platform/lib/locale/org-openide-util-ui_es.jar:/usr/share/netbeans-nb-8.1/platform/lib/locale/org-openide-util_es.jar:/opt/oracle-jdk-bin-1.8.0.66/lib/dt.jar:/opt/oracle-jdk-bin-1.8.0.66/lib/tools.jar" -Dnetbeans.default_userdir_root="/home//sibok/.netbeans" -Dnetbeans.running.environment=kde -Dnetbeans.dirs="/usr/share/netbeans-nb-8.1/nb:/usr/share/netbeans-nb-8.1/ergonomics:/usr/share/netbeans-nb-8.1/ide:/usr/share/netbeans-nb-8.1/extide:/usr/share/netbeans-nb-8.1/java:/usr/share/netbeans-nb-8.1/apisupport:/usr/share/netbeans-nb-8.1/webcommon:/usr/share/netbeans-nb-8.1/websvccommon:/usr/share/netbeans-nb-8.1/enterprise:/usr/share/netbeans-nb-8.1/mobility:/usr/share/netbeans-nb-8.1/profiler:/usr/share/netbeans-nb-8.1/python:/usr/share/netbeans-nb-8.1/php:/usr/share/netbeans-nb-8.1/identity:/usr/share/netbeans-nb-8.1/harness:/usr/share/netbeans-nb-8.1/cnd:/usr/share/netbeans-nb-8.1/cndext:/usr/share/netbeans-nb-8.1/dlight:/usr/share/netbeans-nb-8.1/groovy:/usr/share/netbeans-nb-8.1/extra:/usr/share/netbeans-nb-8.1/javacard:/usr/share/netbeans-nb-8.1/javafx:" -Dnetbeans.home="/usr/share/netbeans-nb-8.1/platform" '-Dnetbeans.importclass=org.netbeans.upgrade.AutoUpgrade' '-Dnetbeans.accept_license_class=org.netbeans.license.AcceptLicense' '-Xmx1024m' '-client' '-Xss2m' '-Xms32m' '-Dapple.laf.useScreenMenuBar=true' '-Dapple.awt.graphics.UseQuartz=true' '-Dsun.java2d.noddraw=true' '-Dsun.java2d.dpiaware=true' '-Dsun.zip.disableMemoryMapping=true' -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath="/home//sibok/.netbeans/8.1/var/log/heapdump.hprof" -splash:"/home//sibok/.cache/netbeans/8.1/splash.png" org.netbeans.Main --cachedir "/home//sibok/.cache/netbeans/8.1" --userdir "/home//sibok/.netbeans/8.1" "-branding" "nb" 0<&0

I've just uploaded the kernel .config file