### Question:
Column implements Cloneable { public void convertToDouble() { if (value.isPresent()) { String asString = String.valueOf(value.get()); if (asString.isEmpty()) { this.value = Optional.of((double) 0); return; } try { this.value = Optional.of(Double.parseDouble(asString)); } catch (NumberFormatException ex) { throw new NumberFormatException("Cannot convert column: " + this.name + " with index " + this.index + " and value ->" + this.value + "<- to double"); } } } Column(int index, String name, Object value);  Column(int index, String name, String targetSink, Object value);  Column(int index, String name); void convertToInteger(); void convertToDouble(); void convertDMSToDouble(); void convertToBoolean(); void fillWithValue(String value); void convertToString(); boolean isNullValue(); String getName(); Object getValue(); Optional<Object> getValueAsOptional(); int getIndex(); void setIndex(int index); String getTargetSink(); String getTargetObject(); void setName(String name); void setTargetSink(String targetSink); void setTargetObject(String targetObject); void setValue(Object value); @Override int hashCode(); @Override boolean equals(Object obj); @Override Column clone(); @Override String toString();  }### Answer:
@Test public void convertToDouble() { Column column = new Column(0, "name", "42.0"); column.convertToDouble(); assertTrue(column.getValue() instanceof Double); }