Nashorn can show an assertion failure when converting arrays of floats.
This worked in 1.8.0_31, fails in 1.8.0_40, 1.8.0_45.

function floatTest() {
    var jsArray = [35250.123456789];
    var jFloat = Java.to(jsArray, "float[]");
    print(j2jsarray(jFloat));
}

function j2jsarray(jArray) {
    var out = new Array();
    // out[0]=1.2; this will avoid the assertion failure.
    for (var i = 0; i < jArray.length; i++) {
        out[i] = jArray[i];
    }
    return out;
}

floatTest();


Exception in thread "main" java.lang.AssertionError
at
jdk.nashorn.internal.runtime.arrays.IntArrayData.convert(IntArrayData.java:191
)
at
jdk.nashorn.internal.runtime.arrays.IntArrayData.set(IntArrayData.java:241)
at
jdk.nashorn.internal.runtime.ScriptObject.doesNotHave(ScriptObject.java:3166)
at jdk.nashorn.internal.runtime.ScriptObject.set(ScriptObject.java:3384)
at
jdk.nashorn.internal.scripts.Script$Recompilation$2$167A$\^eval\_.j2jsarray(<e
val>:12)
at
jdk.nashorn.internal.scripts.Script$Recompilation$1$22$\^eval\_.floatTest(<eva
l>:5)
at jdk.nashorn.internal.scripts.Script$\^eval\_.:program(<eval>:17)
at
jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java
:636)
at
jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:229)
at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:387)
at
jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.jav
a:437)
at
jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.jav
a:401)
at
jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.jav
a:397)
at
jdk.nashorn.api.scripting.NashornScriptEngine.eval(NashornScriptEngine.java:14
7)
at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:249)
at FloatTestApp.main(FloatTestApp.java:13)